ProAssurance Corporation (ProAssurance, PRA or the Company), a Delaware corporation, is an insurance holding company primarily for wholly owned specialty property and casualty and workers' compensation insurance entities including an entity that provides capital to Syndicate 1729 at Lloyd's. Risks insured are primarily liability risks located within the U.S.

ProAssurance operates in five reportable segments as follows: Specialty P&C, Workers' Compensation Insurance, Segregated Portfolio Cell Reinsurance, Lloyd's Syndicates and Corporate. For more information on the Company's segment reporting, including the nature of products and services provided and financial information by segment, refer to Note 18.

The accompanying consolidated financial statements include the accounts of ProAssurance Corporation, its wholly owned subsidiaries and VIEs in which ProAssurance is the primary beneficiary. See Note 16 for more information on ProAssurance's VIE interests. Investments in entities where ProAssurance holds a greater than minor interest but does not hold a controlling interest are accounted for using the equity method. All significant intercompany accounts and transactions are eliminated in consolidation. ProAssurance subsidiaries located in the U.K. are normally reported on a quarter lag due to timing issues regarding the availability of information, except when information is available that is material to the current period. Furthermore, investment results associated with ProAssurance's FAL investments and certain U.S. paid administrative expenses are reported concurrently as that information is available on an earlier time frame.

The significant accounting policies followed by ProAssurance in making estimates that materially affect financial reporting are summarized in these Notes to Consolidated Financial Statements. The Company evaluates these estimates and assumptions on an ongoing basis based on current and historical developments, market conditions, industry trends and other information that the Company believes to be reasonable under the circumstances, including the potential impacts of the COVID-19 pandemic (see "Item 1A, Risk Factors" included in this report for additional information). The Company can make no assurance that actual results will conform to its estimates and assumptions; reported results of operations may be materially affected by changes in these estimates and assumptions.

ProAssurance establishes its reserve for losses and LAE ("reserve for losses" or "reserve") based on estimates of the future amounts necessary to pay claims and expenses associated with the investigation and settlement of claims. The reserve for losses is determined on the basis of individual claims and payments thereon as well as actuarially determined estimates of future losses based on past loss experience, available industry data and projections as to future claims frequency, severity, inflationary trends, judicial trends, legislative changes and settlement patterns.

Management establishes the reserve for losses after taking into consideration a variety of factors including premium rates, historical paid and incurred loss development trends, and management's evaluation of the current loss environment including frequency, severity, expected effect of inflation, general economic and social trends, and the legal and political environment.

Management also takes into consideration the conclusions reached by internal and consulting actuaries. Management updates and reviews the data underlying the estimation of the reserve for losses each reporting period and makes adjustments to loss estimation assumptions that best reflect emerging data. Both internal and consulting actuaries perform an in-depth review of the reserve for losses on at least a semi-annual basis using the loss and exposure data of ProAssurance's subsidiaries. Consulting actuaries provide reports to management regarding the adequacy of reserves.

Estimating casualty insurance reserves, and particularly long-tailed insurance reserves, is a complex process. Long-tailed insurance is characterized by the extended period of time typically required both to assess the viability of a claim and potential damages, if any, and to reach a resolution of the claim. For a high proportion of the risks insured or reinsured by ProAssurance, the period of time required to resolve a claim is often five years or more, and claims may be subject to litigation. Estimating losses for these long-tailed claims requires ProAssurance to make and revise judgments and assessments regarding multiple uncertainties over an extended period of time. As a result, reserve estimates may vary significantly from the eventual outcome. Reserve estimates and the assumptions on which these estimates are predicated are regularly reviewed and updated as new information becomes available. Any adjustments necessary are reflected in current operations. Due to the size of ProAssurance’s reserve for losses, even a small percentage adjustment to these estimates could have a material effect on earnings in the period in which the adjustment is made, as was the case in 2021, 2020 and 2019. See Note 10 for additional information on ProAssurance's reserve for losses and LAE.

ProAssurance enters into reinsurance agreements whereby other insurance entities agree to assume a portion of the risk associated with certain policies issued by ProAssurance. In return, ProAssurance agrees to pay a premium to the reinsurer. ProAssurance uses reinsurance to provide capacity to write larger limits of liability, to provide reimbursement for losses incurred under the higher limit coverages the Company offers, to provide protection against losses in excess of policy limits, and, in the case of risk sharing arrangements, to align the Company's objectives with those of its strategic business partners and to provide custom insurance solutions for large customer groups.

Receivable from reinsurers on paid losses and LAE is the estimated amount of losses already paid that will be recoverable from reinsurers. Receivable from reinsurers on unpaid losses and LAE is the estimated amount of future loss payments that will be recoverable from reinsurers. Reinsurance recoveries are the portion of losses incurred during the period that are estimated to be allocable to reinsurers. Premiums ceded are the estimated premiums that will be due to reinsurers with respect to premiums earned and losses incurred during the period.

These estimates are based upon management’s estimates of ultimate losses and the portion of those losses that are allocable to reinsurers under the terms of the related reinsurance agreements. Given the uncertainty inherent in management's estimate of the ultimate amounts of losses, these estimates may vary significantly from the ultimate outcome. Management regularly reviews these estimates and any adjustments necessary are reflected in the period in which the estimate is changed. Due to the size of the receivable from reinsurers, an adjustment to these estimates could have a material effect on ProAssurance's results of operations for the period in which the adjustment is made.

Reinsurance contracts do not relieve ProAssurance from its obligations to policyholders. ProAssurance continually monitors its reinsurers to minimize its exposure to significant credit losses from reinsurer insolvencies (see additional discussion below under the heading "Credit Losses"). Any amount determined to be uncollectible is written off in the period in which the uncollectible amount is identified. See Note 6 for further information.

ProAssurance's premiums receivable and reinsurance receivables are exposed to credit losses but to-date have not experienced any significant amount of credit losses. ProAssurance measures expected credit losses on its premiums receivables and reinsurance receivables on a collective (pool) basis when similar risk characteristics exist, and the Company will reassess its pools each reporting period to ensure all receivables within the pool continue to share similar risk characteristics. If the Company determines that a receivable does not share risk characteristics with its other receivables within a pool, it will evaluate that receivable for expected credit losses on an individual basis. ProAssurance measures expected credit losses associated with its premium receivables at the segment level as each segment’s premium receivables share similar risk characteristics including term, type of financial asset and similar historical and expected credit loss patterns. ProAssurance measures expected credit losses associated with its reinsurance receivables (related to both paid and unpaid losses) at the consolidated level as its

ProAssurance measures expected credit losses over the contractual term of each pool utilizing a loss rate method. Historical internal credit loss experience for each pool is the basis for the Company’s assessment of expected credit losses; however, the Company may also consider historical credit loss information from external sources. In addition to historical credit loss data, the Company also considers reasonable and supportable forecasts of future economic conditions in its estimate of expected credit losses by utilizing industry and macroeconomic factors that it believes most relevant to the collectability of each pool.

ProAssurance's premiums receivable on its Consolidated Balance Sheet as of December 31, 2021 and 2020 is reported net of the related allowance for expected credit losses of $7.4 million and $6.1 million, respectively. The following tables present a roll forward of the allowance for expected credit losses related to the Company's premiums receivable for the years ended December 31, 2021 and 2020.


(In thousands)	Premiums Receivable, Net		Allowance for Expected Credit Losses
Balance, December 31, 2020	$	201,395	$	6,131


Initial allowance recognized in the period for NORCAL premiums receivable(1)			2,137
Provision for expected credit losses			439
Write offs charged against the allowance			(1,533)
Recoveries of amounts previously written off			262
Balance, December 31, 2021	$	241,095	$	7,436


(In thousands)	Premiums Receivable, Net		Allowance for Expected Credit Losses
Balance, December 31, 2019	$	249,540	$	1,590
Cumulative-effect adjustment, before tax(2)			5,160
Provision for expected credit losses			827

Write offs charged against the allowance			(2,019)
Recoveries of amounts previously written off			573
Balance, December 31, 2020	$	201,395	$	6,131
(1) Represents an initial allowance for expected credit losses recognized during the second quarter of 2021 for NORCAL's premiums receivable to conform NORCAL to ProAssurance's accounting policies. See Note 2 for more information.
(2) Due to the adoption of ASU 2016-13, ProAssurance recorded a cumulative-effect adjustment to beginning retained earnings as of January 1, 2020 to increase its consolidated allowance for expected credit losses related to its premiums receivable.

ProAssurance's expected credit losses associated with its reinsurance receivables (related to both paid and unpaid losses) were nominal in amount as of December 31, 2021 and 2020. ProAssurance has other financial assets and off-balance-sheet commitments that are exposed to credit losses; however, expected credit losses associated with these assets and commitments were nominal in amount as of December 31, 2021 and 2020.

Under the retroactive provisions of a contract, all premiums received and losses assumed are recognized immediately in earnings at the inception of the contract as all of the underlying loss events occurred in the past. If the estimated losses assumed differ from the premium received related to the retroactive provision of a contract, the resulting difference is deferred and recognized over the estimated claim payment period with the periodic amortization reflected in earnings as a component of net losses and LAE. Deferred gains are included as a component of the reserve for losses and LAE, and deferred losses are included

as a component of other assets on the Consolidated Balance Sheets. Subsequent changes to the estimated timing or amount of future loss payments in relation to the losses assumed under retroactive provisions also produce changes in deferred balances. Changes in such estimates are applied retrospectively, and the resulting changes in deferred balances, together with periodic amortization, are included in earnings in the period of change. See Note 5 for more information.

Fair values of investment securities are primarily provided by independent pricing services. The pricing services provide an exchange-traded price, if available, or provide an estimated price determined using multiple observable inputs, including exchange-traded prices for similar assets. Management reviews valuations of securities obtained from the pricing services for accuracy based upon the specifics of the security, including class, maturity, credit rating, durations, collateral and comparable markets for similar securities. Multiple observable inputs are not available for certain of the Company's investments, including corporate debt not actively traded, certain asset-backed securities and investments in LPs/LLCs. Management values the corporate debt not actively traded and the other asset-backed securities either using dealer quotes for similar securities or discounted cash flow models using yields currently available for similar securities. Management values certain investment funds, primarily LPs/LLCs, based on the NAV of the interest held, as provided by the fund.

Management measures the fair value of certain assets on a nonrecurring basis when events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. These assets include investments carried principally at cost, investments in tax credit partnerships, fixed assets, goodwill and other intangible assets. These assets would also include any equity method investments that do not provide a NAV.

Available-for-sale securities are carried at fair value, determined as described above and in Note 3. Exclusive of impairment losses, discussed in a separate section that follows, unrealized holding gains and losses on available-for-sale securities are included, net of related tax effects, as a component of OCI in the Consolidated Statement of Income and Comprehensive Income during the period of change and as a component AOCI in shareholders' equity on the Consolidated Balance Sheet.

Equity investments are carried at fair value, as described above, with the holding gains and losses included as a component of net investment gains (losses) in the Consolidated Statement of Income and Comprehensive Income during the period of change. Equity investments are primarily comprised of stocks, bond funds and investment funds.

Equity investments, primarily investments in LPs/LLCs, where ProAssurance is deemed to have influence because it holds a greater than a minor interest are accounted for using the equity method. Under the equity method, the recorded basis of the investment is adjusted each period for the investor’s pro rata share of the investee’s income or loss. Investments in unconsolidated subsidiaries include tax credit partnerships accounted for using the equity method, whereby ProAssurance’s proportionate share of income or loss is included in equity in earnings (loss) of unconsolidated subsidiaries. Tax credits received from the partnerships are recognized in the period received in the Consolidated Statements of Income and Comprehensive Income as either a reduction to current tax expense or as a component of deferred tax expense if they cannot be utilized in the period received.

ProAssurance owns life insurance contracts on certain management employees, which includes policies acquired from NORCAL. The life insurance contracts are carried at their current cash surrender value. Changes in the cash surrender value are included in income in the current period as investment income. Death proceeds from the contracts are recorded when the proceeds become payable under the policy terms.

ProAssurance evaluates its available-for-sale investment securities, which at December 31, 2021 and 2020 consisted entirely of fixed maturity securities, on at least a quarterly basis for the purpose of determining whether declines in fair value below recorded cost basis represent a credit loss. The Company considers a credit loss to have occurred:

The assessment of whether the amortized cost basis of a security is expected to be recovered requires the Company to make assumptions regarding various matters affecting future cash flows. The choice of assumptions is subjective and requires the use of judgment. Actual credit losses experienced in future periods may differ from the Company’s estimates of those credit losses. Methodologies used to estimate the present value of expected cash flows are:

If deemed appropriate and necessary, a discounted cash flow analysis is performed to confirm whether a credit loss exists and, if so, the amount of the credit loss. ProAssurance uses the single best estimate approach for available-for-sale debt securities and considers all reasonably available data points, including industry analyses, credit ratings, expected defaults and the remaining payment terms of the debt security. For fixed rate available-for-sale debt securities, cash flows are discounted at the security's effective interest rate implicit in the security at the date of acquisition. If the available-for-sale debt security’s contractual interest rate varies based on subsequent changes in an independent factor, such as an index or rate, for example, the prime rate, the LIBOR, or the U.S. Treasury bill weekly average, that security’s effective interest rate is calculated based on the factor as it changes over the life of the security.

If ProAssurance intends to sell a debt security or believes it will more likely than not be required to sell a debt security before the amortized cost basis is recovered, any existing allowance will be written off against the security's amortized cost basis, with any remaining difference between the debt security's amortized cost basis and fair value recognized as an impairment loss in earnings.

Exclusive of securities where there is an intent to sell or where it is not more likely than not that the security will be required to be sold before recovery of its amortized cost basis, impairment for debt securities is separated into a credit component and a non-credit component. The credit component of an impairment is the difference between the security’s amortized cost basis and the present value of its expected future cash flows, while the non-credit component is the remaining difference between the security’s fair value and the present value of expected future cash flows. An allowance for expected credit losses will be recorded for the expected credit losses through income and the non-credit component is recognized in OCI. The amount of impairment recognized is limited to the excess of the amortized cost over the fair value of the available-for-sale debt security.

ProAssurance records derivative instruments at fair value in the Consolidated Balance Sheets. ProAssurance accounts for the changes in fair value of derivatives depending on whether the derivative is designated as a hedging instrument and if so, the type of hedging relationship. For derivative instruments not designated as hedging instruments, ProAssurance recognizes the change in fair value of the derivative in earnings during the period of change. As of December 31, 2021 and 2020, ProAssurance has not designated any derivative instruments as hedging instruments and does not use derivative instruments for trading purposes.

The functional currency of all ProAssurance foreign subsidiaries is the U.S. dollar. In recording foreign currency transactions, revenue and expense items are converted to U.S. dollars at the exchange rate prevailing at the transaction date. Monetary assets and liabilities originating in currencies other than the U.S. dollar are remeasured to U.S. dollars at the rates of exchange in effect as of the balance sheet date. The resulting foreign currency gains or losses are recognized in the Consolidated Statements of Income and Comprehensive Income as a component of other income. Monetary assets and liabilities include investments, cash and cash equivalents, accrued expenses and other liabilities. In addition, monetary assets and liabilities include certain premiums receivable and reserve for losses and LAE as a result of reinsurance transactions conducted with foreign cedents denominated in their local functional currencies.

The Company uses December 31 as the measurement date for calculating its obligation related to this defined benefit pension plan and for estimating net periodic benefit cost (credit) for the subsequent year. The PBO for pension benefits represents the present value of all future benefits earned as of the measurement date for vested and non-vested employees. At each measurement date, the Company reviews the various assumptions impacting the amounts recorded for the pension plan including the discount rates, which impacts the recorded value of the PBO and interest costs, and the expected return on plan assets.

To estimate the discount rate at the measurement date, the Company uses a bond yield curve model, developed based on pricing and yield information for high quality corporate bonds. The assumption for the expected return on plan assets is based on the anticipated returns that will be earned by the portfolio over the long term. The expected return is influenced, but not determined, by historical portfolio performance.

Accounting standards provide for the delayed recognition of differences between actual results and expected or estimated results. This delayed recognition of the differences is amortized into earnings over time. The differences between actual results and expected or estimated results are recognized in full in AOCI. Amounts recognized in AOCI are reclassified to earnings in a systematic manner over the average future service period of participants.

Costs that vary with and are directly related to the successful production of new and renewal premiums (primarily premium taxes, commissions and underwriting salaries) are deferred to the extent they are recoverable against unearned premiums and are amortized as related premiums are earned. Unearned ceding commission income is reported as an offset to DPAC, and ceding commission earned is reported as an offset to DPAC amortization.

ProAssurance evaluates the recoverability of DPAC typically at the segment level each reporting period, or in a manner that is consistent with the way the Company manages its business. Any amounts estimated to be unrecoverable are charged to expense in the current period. As part of the evaluation of the recoverability of DPAC, ProAssurance also evaluates unearned premium for premium deficiencies. A premium deficiency is recognized if the sum of anticipated losses and loss adjustment expenses, unamortized DPAC and maintenance costs, net of anticipated investment income, exceeds the related unearned premium. If a premium deficiency is identified, the associated DPAC is written off, and a PDR is recorded for the excess deficiency as a component of net losses and loss adjustment expenses in the Consolidated Statements of Income and Comprehensive Income and as a component of the reserve for losses on the Consolidated Balance Sheets.

ProAssurance evaluates tax positions taken on tax returns and recognizes positions in the financial statements when it is more likely than not that the position will be sustained upon resolution with a taxing authority. If recognized, the benefit is measured as the largest amount of benefit that has a greater than fifty percent probability of being realized. Uncertain tax positions are reviewed each period by considering changes in facts and circumstances, such as changes in tax law, interactions with taxing authorities and developments in case law, and adjustments would be made if considered necessary. Adjustments to unrecognized tax benefits may affect income tax expense, and the settlement of uncertain tax positions may require the use of cash. Other than differences related to timing, no significant adjustments were considered necessary during the years ended December 31, 2021 or 2020.

Deferred federal income taxes arise from the recognition of temporary differences between the basis of assets and liabilities determined for financial reporting purposes and the basis determined for income tax purposes. ProAssurance’s temporary differences principally relate to loss reserves, unearned and advanced premiums, DPAC, NOL and tax credit carryforwards, compensation related items, unrealized investment gains (losses) and basis differentials in fixed assets, intangible assets and operating leases. Deferred tax assets and liabilities are measured using the enacted tax rates expected to be in effect when such benefits are realized. ProAssurance reviews its deferred tax assets quarterly for impairment. If management determines that it is more likely than not that some or all of a deferred tax asset will not be realized, a valuation allowance is recorded to reduce the carrying value of the asset. In assessing the need for a valuation allowance, management is required to make certain judgments and assumptions about the future operations of ProAssurance based on historical experience and information as of the measurement period regarding reversal of existing temporary differences, carryback capacity, future taxable income of the appropriate character (including its capital and operating characteristics) and tax planning strategies.

Intangible assets with definite lives are amortized over the estimated useful life of the asset. Amortizable intangible assets primarily consist of policyholder relationships, renewal rights and trade names. Intangible assets with an indefinite life, primarily state licenses, are not amortized. Indefinite lived intangible assets are evaluated for impairment on an annual basis or upon the occurrence of certain triggering events or substantive changes in circumstances that indicate the intangible asset may be impaired. Amortizable intangible assets and other long-lived assets are tested for impairment at the asset group level upon the occurrence of certain triggering events or substantive changes in circumstances that indicate the carrying amount of the asset group may not be recoverable. An impairment loss is recognized when estimated undiscounted future cash flows expected to result from the use of the asset group are less than the carrying amounts of the related asset group. Impairment losses are measured as the amount by which the carrying amount of the asset groups exceed their fair values. The Company's asset groups generally correspond to the same level at which goodwill is tested for impairment. The following table provides additional information regarding ProAssurance's intangible assets.

Impairment of goodwill is tested at the reporting unit level, which is consistent with the Company's reportable segments identified in Note 18. Of the Company's five reporting units, two have net goodwill: Workers' Compensation Insurance and Segregated Portfolio Cell Reinsurance. See Note 8 for additional information about the Company's assessment of goodwill.

When testing goodwill for impairment on the Company's annual test date, it has the option to first assess qualitative factors to determine whether the existence of events or circumstances leads to a determination that it is more likely than not that the estimated fair value of a reporting unit is less than its carrying amount. If the Company elects to perform a qualitative assessment and determine that an impairment is more likely than not, the Company is then required to perform a quantitative impairment test; otherwise, no further analysis is required. The Company also may elect not to perform the qualitative assessment and, instead, proceed directly to the quantitative impairment test.

Performance of the qualitative goodwill impairment assessment requires judgment in identifying and considering the significance of relevant key factors, events, and circumstances that affect the fair values of the Company's reporting units. This requires consideration and assessment of external factors such as macroeconomic, industry, and market conditions, as well as entity-specific factors, such as the Company's actual and planned financial performance. The Company also gives consideration to the difference between each reporting unit's fair value and carrying value as of the most recent date that a fair value measurement was performed. If the results of the qualitative assessment conclude that it is not more likely than not that the fair value of a reporting unit exceeds its carrying value, additional quantitative impairment testing is performed.

The quantitative goodwill impairment test involves comparing the fair value of a reporting unit with its carrying value including goodwill. If the fair value of a reporting unit exceeds its carrying value, the reporting unit's goodwill is considered not to be impaired. However, if the carrying value of a reporting unit exceeds its fair value, an impairment loss is recorded in an amount equal to that excess. Any impairment charge recognized is limited to the amount of the respective reporting unit's allocated goodwill.

Determining the fair value of a reporting unit under the quantitative goodwill impairment test requires judgment and often involves the use of significant estimates and assumptions, including an assessment of external factors such as macroeconomic, industry, and market conditions, as well as entity-specific factors, such as actual and planned financial performance. These estimates and assumptions could have a significant impact on whether or not an impairment charge is recognized and the magnitude of any such charge. To assist management in the process of determining any potential goodwill impairment, the Company may review and consider appraisals from accredited independent valuation firms. Estimates of fair value are primarily determined using discounted cash flows and market comparisons. These approaches involve significant estimates and assumptions, including projected future cash flows (including timing), discount rates reflecting the risks inherent in those future cash flows, perpetual growth rates, and selection of appropriate market comparable metrics and transactions.

The Company accounted for its acquisition of NORCAL in accordance with GAAP relating to business combinations which required management to make certain estimates and assumptions including determining the fair value of the non-cash components of the acquisition consideration and the acquisition date fair values of the acquired tangible and identifiable intangible assets and assumed liabilities of NORCAL. Subsequent to the preliminary valuation of the non-cash components of the purchase consideration and net assets acquired, any adjustment identified associated with the purchase price allocation will be evaluated to determine whether the adjustment represents a measurement period adjustment in accordance with GAAP. If the adjustment is deemed to be a measurement period adjustment and is identified within one year of the acquisition, then the measurement period adjustment will be recorded in the current reporting period with a corresponding adjustment to the gain on bargain purchase.

VOBA is based on actuarially determined projections and reflects the estimated fair value of in-force contracts acquired in a business combination. VOBA is recorded as an asset when the in-force contracts acquired are expected to generate underwriting income and is recorded as a liability when the in-force contracts acquired are expected to generate an underwriting loss. VOBA liabilities (negative VOBA) are recorded as a component of the reserve for losses and loss adjustment expenses on the Consolidated Balance Sheets. To the extent negative VOBA relates to unearned premium, it is amortized over a period in proportion to the earn-out of the premium as a reduction to current accident year net losses and loss adjustment expenses. To the extent negative VOBA relates to the DDR reserve, it is amortized over a period in proportion to the approximate consumption of losses as a reduction to prior accident year net losses and loss adjustment expenses. See Note 2 for more information.

ProAssurance is involved in a number of leases, primarily for office facilities. The Company determines if an arrangement is a lease at the inception date of the contract and classifies all leases as either financing or operating. Operating leases are included in operating lease ROU assets and operating lease liabilities on the Consolidated Balance Sheets. The ROU asset represents the right to use the underlying asset for the lease term. As of December 31, 2021, ProAssurance has no leases that are classified as financing leases.

Operating ROU assets and operating lease liabilities are initially recognized as of the lease commencement date based on the present value of the remaining lease payments, discounted over the term of the lease using a discount rate determined based on information available as of the commencement date. As the majority of ProAssurance's lessors do not provide an implicit discount rate, the Company uses its collateralized incremental borrowing rate in determining the present value of remaining lease payments. Due to the adoption of ASU 2016-02, the Company used its collateralized incremental borrowing rate as of January 1, 2019 for operating leases that commenced prior to that date. Subsequent to the initial recognition, the operating ROU asset and operating lease liability are amortized and accreted, respectively, over the lease term in a manner that results in a straight-line operating lease expense. Operating lease expense is included as a component of operating expense on the Consolidated Statements of Income and Comprehensive Income for the years ended December 31, 2021, 2020 and 2019. Leases with an initial term of twelve months or less are considered short-term and are not recorded on the Consolidated Balance Sheet; lease expense for these leases is also recognized on a straight-line basis over the lease term. Additionally, for leases entered into or reassessed after the adoption of ASU 2016-02 on January 1, 2019, ProAssurance accounts for lease and non-lease components of a contract as a single lease component.

Operating lease ROU assets are evaluated for impairment at the asset group level whenever events or changes in circumstances indicate that the carrying amount of the asset group may not be recoverable. The carrying amount of an asset group, which includes the operating lease ROU asset and the related operating lease liability, is not recoverable if the carrying amount exceeds the sum of the undiscounted cash flows expected to result from the use of the asset group over the life of the primary asset in the asset group. That assessment is based on the carrying amount of the asset group, including the operating lease ROU asset and the related operating lease liability, at the date it is tested for recoverability and an impairment loss is measured and recognized as the amount by which the carrying amount of the asset group exceeds its fair value. Any impairment loss is allocated to each asset in the asset group, including the operating ROU asset.

When a lease of an office facility is to be abandoned and will not be subleased, the Company first evaluates whether or not the operating lease ROU asset’s inclusion in an existing asset group continues to be appropriate and if the commitment to abandon the lease constitutes a change in circumstances requiring the operating lease ROU asset, or the larger asset group, to be tested for impairment. If an impairment test is required, it is performed in the same manner as discussed above. Any remaining carrying value of the operating lease ROU asset is amortized from the date the Company commits to a plan to abandon the lease to the expected date that the Company will cease to use the leased property. Leases to be abandoned in which the Company has the intent or practical ability to sublease continue to be accounted for under a held and use model, with no change to the amortization period of the operating lease ROU asset, and are evaluated for impairment as a separate asset group at the date the sublease is executed.

Real Estate balances are reported at cost or, for properties acquired in business combinations, estimated fair value on the date of acquisition, less accumulated depreciation. Real estate principally consists of properties in use as corporate offices. Depreciation is computed over the estimated useful lives of the related property using the straight-line method. Excess office capacity is leased or made available for lease; rental income is included in other income, and real estate expenses are included in operating expense.

Workers’ compensation premiums are determined based upon the payroll of the insured, the applicable premium rates and an experience-based modification factor, where applicable. An audit of the policyholders’ records is conducted after policy expiration to make a final determination of applicable premiums. Audit premium due from or due to a policyholder as a result of an audit is reflected in net premiums written and earned when billed. ProAssurance tracks, by policy, the amount of additional premium billed in final audit invoices as a percentage of payroll exposure and uses this information to estimate the probable additional amount of EBUB as of the balance sheet date. Changes to the EBUB estimate are included in net premiums written and earned in the period recognized. As of December 31, 2021 and 2020, ProAssurance carried EBUB of $1.8 million and $3.0 million, respectively, as a part of premiums receivable. As a result of the economic impact of COVID-19, the Company recognized reductions in payroll exposure related to in-force policies that resulted in a significant decrease in audit premium and a reduction in our EBUB estimate during 2021 and 2020. ProAssurance will continue to monitor and adjust the estimate, if necessary, based on changes in insured payrolls and economic conditions, as experience develops or new information becomes known; however, the length and magnitude of such changes depends on future developments, which are highly uncertain and cannot be predicted.

For certain insurance policies and reinsurance contracts written in the Lloyd’s Syndicates segment, premiums are initially recognized based upon estimates of ultimate premium. Estimated ultimate premium consists primarily of premium written under delegated underwriting authority arrangements, which consist primarily of binding authorities, and certain assumed reinsurance agreements. These estimates of ultimate premium are judgmental and are dependent upon certain assumptions, including historical premium trends for similar agreements. As reports are received from programs, ultimate premium estimates are revised, if necessary, with changes reflected in current operations.

Other assets include the acquired NORCAL investments in a deferred compensation rabbi trust which are carried at fair value. These rabbi trust assets are related to other liabilities associated with funded deferred compensation agreements with NORCAL employees and previous members of NORCAL's Board of Directors.

Other liabilities include the assumed NORCAL liability for deferred compensation balances associated with the rabbi trust assets and the reported balance is determined based on the amount of elective deferrals and employer contributions adjusted for periodic changes in fair value of the participant balances based on the performance of the funds selected by the participants.

Deferred compensation liabilities represent the amount of elective deferrals and employer contributions adjusted for periodic changes in the fair value of the participant balances based on the performance of the funds selected by the participants. See additional information on the deferred compensation liabilities in Note 3.

Compensation cost for share-based payments is measured based on the grant-date fair value of the award, recognized over the period in which the employee is required to provide service in exchange for the award. Excess tax benefits (tax deductions realized in excess of the compensation costs recognized for the exercise of the awards, multiplied by the incremental tax rate) are reported as operating cash inflows.

Effective for fiscal years beginning after December 15, 2020 and interim periods within those fiscal years, the FASB amended guidance that clarifies the accounting for the transition into and out of the equity method and measuring certain purchased options and forward contracts to acquire investments. ProAssurance adopted the guidance beginning January 1, 2021, and adoption had no material effect on ProAssurance's results of operations, financial position or cash flows.