Summary of Significant Accounting Policies (Policies)

9 Months Ended

Sep. 30, 2020

Basis of presentation and principals of consolidation

Basis of presentation and principals of consolidation – The accompanying unaudited condensed financial statements have been prepared in accordance with accounting principles generally accepted in the United States of America ("GAAP") for interim financial information and with the instructions to Form 10-Q and Article 8 Regulation S-X. Accordingly, they do not include all of the information and notes required by GAAP for annual financial statements. The condensed financial statements and notes should be read in conjunction with the consolidated financial statements and notes for the year ended December 31, 2019 included in the Company's Annual Report on Form 10-K for the year ended December 31, 2019, as filed with the Securities and Exchange Commission on March 30, 2020. In the opinion of management, all adjustments, consisting of normal accruals, considered necessary for a fair presentation of the interim financial statements have been included. Results for the nine months ended September 30, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020.

Recently adopted accounting pronouncements

Recently adopted accounting pronouncements - New accounting pronouncements implemented by the Company are discussed below or in the related notes, where appropriate.

In August 2018, the Financial Accounting Standards Board ("FASB") issued Accounting Standards Update ("ASU") No. 2018-13, “Disclosure Framework — Changes to the Disclosure Requirements for Fair Value Measurement” (“ASU 2018-13”). This ASU amends ASC 820 to add, remove and modify certain disclosure requirements for fair value measurements. For example, public companies will be required to disclose the range and weighted average used to develop significant unobservable inputs for Level 3 fair value measurements. The Company adopted ASU 2018-13 effective January 1, 2020. The adoption of this guidance did not have a material impact on the Company's financial position, results of operations or cash flow.

In June 2016, the FASB issued ASU 2016-13, “Financial Instruments – Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.” This update will require the measurement of all expected credit losses for financial assets, including trade receivables, held at the reporting date based on historical experience, current conditions and reasonable and supportable forecasts. The guidance was initially effective for the Company for annual reporting periods beginning after December 15, 2019 and interim periods within those fiscal years. In November 2019, the FASB issued ASU 2019-10, “Financial Instruments – Credit Losses (Topic 326), Derivatives and Hedging (Topic 815), and Leases (Topic 842): Effective Dates,” which, among other things, defers the effective date of ASU 2016-13 for public filers that are considered smaller reporting companies as defined by the SEC to fiscal years beginning after December 15, 2022, including interim periods within those years. Early adoption is permitted. The Company adopted ASU 2016-13 effective January 1, 2020. The adoption of this guidance did not have a material impact on the Company's financial position, results of operations or cash flow.

Accounting estimates

Accounting estimates – The preparation of condensed consolidated financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities at the date of the financial statements and the reported amount of revenues and expenses during the reporting period. Significant areas that require the Company to make estimates include revenue recognition, stock-based compensation, stock warrants liabilities and allowance for credit losses. Actual results could differ from those estimates.

Operating cycle

Operating cycle – The length of the Company’s contracts varies, but is typically between six to twelve months. In some instances, the length of the contract may exceed twelve months. Assets and liabilities relating to contracts are included in current assets and current liabilities, respectively, in the accompanying balance sheets as they will be liquidated in the normal course of contract completion, which at times could exceed one year.

Revenue recognition

Revenue recognition – The Company applies recognition of revenue over time, which is similar to the method the Company applied under previous guidance (i.e., percentage of completion). The Company determines, at contract inception, whether it will transfer control of a promised good or service over time or at a point in time, regardless of the length of contract or other factors. The recognition of revenue aligns with the timing of when promised goods or services are transferred to customers in an amount that reflects the consideration to which the Company expects to be entitled in exchange for those goods or services. To achieve this core principle, the Company applies the following five steps in accordance with its revenue policy:

(1) Identify the contract with a customer

(2) Identify the performance obligations in the contract

(3) Determine the transaction price

(4) Allocate the transaction price to performance obligations in the contract

(5) Recognize revenue as performance obligations are satisfied

Due to uncertainties inherent in the estimation process, it is possible that estimates of costs to complete a performance obligation will be revised in the near-term. For those performance obligations for which revenue is recognized using a cost-to-cost input method, changes in total estimated costs, and related progress toward complete satisfaction of the performance obligation, are recognized on a cumulative catch-up basis in the period in which the revisions to the estimates are made. When the current estimate of total costs for a performance obligation indicate a loss, a provision for the entire estimated loss on the unsatisfied performance obligation is made in the period in which the loss becomes evident.

On October 3, 2019, the Company entered into an Exclusive License Agreement (“ELA” ) pursuant to which it granted an exclusive license for its technology as outlined in the ELA. The ELA is described below. Under the ELA, the Company will receive royalty payments based upon gross revenues earned by the licensee for commercialized products within the field of design and project management platforms for residential use, including single-family residences and multi-family residences, but excluding military housing. The Company has determined that the ELA grants the licensee a right to access the Company’s intellectual property throughout the license period (or its remaining economic life, if shorter), and thus recognizes revenue over time as the licensee recognizes revenue and the Company has the right to payment of royalties. No revenue has been recognized under the ELA for the nine months ended September 30, 2020.

CMC Right of First Refusal Agreement – On October 9, 2019, the Company entered into a Right of First Refusal Agreement (the “Agreement”) with CMC Development LLC (“CMC”), which has a term of two (2) years. Under the Agreement, the Company has a right of first refusal with respect to being engaged as a designer and builder of any real estate projects for which CMC has secured the rights to develop and in which CMC has a greater than fifty percent (50%) interest in the owner or developer entity and has the right to select the builder for such real estate project (the “ROFR Rights”). In exchange for such ROFR Rights, the Company agreed to issue to CMC 2,500 shares of restricted stock of the Company’s common stock, of which 1,250 shares vested on September 30, 2020 and the remaining 1,250 shares will vest and be issued on September 30, 2021, unless the Agreement is earlier terminated. In the event that the Agreement is earlier terminated, CMC will still be entitled to receive the entire amount of such restricted stock that has vested as of such earlier termination date, but in no event less than 1,250 shares of such restricted stock. The Agreement also provides for customary indemnification and confidentiality obligations between the parties. The 2,500 shares of restricted stock of the Company's common stock has yet to be issued to CMC.

The Agreement also provides that CMC has engaged the Company to build and design, in the aggregate, approximately 100 residential and commercial units at 1100 Ridge Avenue, Atlanta, Georgia, which is known as the “Ridge Avenue, Atlanta Project.” The total value of the project is approximately $16,900,000. The project is a residential project but not subject to the Company’s Exclusive License Agreement, dated October 3, 2019.

In May 2020, the Company and OSANG Healthcare Co., Ltd. ("Osang"), a South Korea based global manufacturer and distributor of medical grade diagnostic tests and equipment, announced the signing of a one year, non-exclusive distributorship agreement for the United States, for OHC's "GeneFinder COVID-19 Plus RealAmp Kit." This is a test designed to detect SARS-CoV-2, the virus that causes COVID-19. The Distributorship Agreement is Osang's standard form of distributorship agreement and provides the Company with the non-exclusive right to distribute Osang's GeneFinder COVID-19 Plus RealAmp Kit in the United States for a stated term of one (1) year. Pursuant to the terms of the Distributorship Agreement, the Company is required to make payment for 100% of any purchase order prior to shipment of the product from Osang, though it does not expect to make any cash outlays with respect to any product that it distributes and expects instead to require any third-party purchasers to make the necessary cash outlays as part of a purchase order entered into with the Company. The Distributorship Agreement does not guarantee the Company a specific quantity of kits to sell or a customer list, and may be terminated by either party at any time on thirty (30) days' notice. To date, the Company has not sold any medical devices or kits and there can be no guarantee that it will be able to establish a sales force, establish distribution channels or solicit customers for the kits. An import license from the U.S. government has been issued to import and distribute the Osang test kits. There can be no assurance that the Distribution Agreement will continue, that it will yield the anticipated benefits or generate significant revenue, if any. No revenue has been recognized under the distribution agreement for the nine months ended September 30, 2020.

Disaggregation of Revenues

The Company’s revenues are principally derived from construction and engineering contracts related to Modules. The Company's contracts are with customers in various industries.

The following tables provide further disaggregation of the Company’s revenues by categories:

	Three Months Ended September 30,
Revenue by Customer Type	2020				2019
Hospitality	$	298,439	52	%	$	—		—	%
Multi-Family (includes Single-Family)		5,003	1	%		(18,013	)	—	%
Office		123,513	21	%		4,424		2	%
Retail		40,952	7	%		195,421		97	%
School		36,500	6	%		—		—	%
Special use		72,153	13	%		—		—	%
Other		—	—	%		2,694		1	%
Total revenue by customer type	$	576,560	100	%	$	184,526		100	%

	Nine Months Ended September 30,
Revenue by Customer Type	2020				2019
Hospitality	$	341,238	24	%	$	—	—	%
Medical (modular structures)		58,533	4	%		—	—	%
Multi-Family (includes Single-Family)		56,966	4	%		94,178	4	%
Office		174,421	12	%		1,212,321	46	%
Retail		364,454	26	%		1,332,805	50	%
School		36,500	3	%		—	—	%
Special Use		72,153	5	%		6,812	—	%
Other (1)		300,000	22	%		1,442	—	%
Total revenue by customer type	$	1,404,265	100	%	$	2,647,558	100	%

(1) Construction fee of $300,000 with no cost of revenue during 2020.

Contract Assets and Contract Liabilities

Accounts receivable are recognized in the period when the Company’s right to consideration is unconditional. Accounts receivable are recognized net of an allowance for credit losses. A considerable amount of judgment is required in assessing the likelihood of realization of receivables.

The timing of revenue recognition may differ from the timing of invoicing to customers.

Contract assets include unbilled amounts from long-term construction services when revenue recognized under the cost-to-cost measure of progress exceeds the amounts invoiced to customers, as the amounts cannot be billed under the terms of our contracts. Such amounts are recoverable from customers based upon various measures of performance, including achievement of certain milestones, completion of specified units or completion of a contract. Contract assets are generally classified as current within the condensed consolidated balance sheets.

Contract liabilities from construction and engineering contracts occur when amounts invoiced to customers exceed revenues recognized under the cost-to-cost measure of progress. Contract liabilities additionally include advanced payments from customers on certain contracts. Contract liabilities decrease as the Company recognizes revenue from the satisfaction of the related performance obligation. Contract liabilities are generally classified as current within the condensed consolidated balance sheet.

Although the Company believes it has established adequate procedures for estimating costs to complete on open contracts, it is at least reasonably possible that additional significant costs could occur on contracts prior to completion. The Company periodically evaluates and revises its estimates and makes adjustments when they are considered necessary.

Deferred Contract Costs - Prior to entering into the ELA, the Company was subject to an agreement to construct and develop a certain property (“Original Agreement”), which now is subject to the ELA. Because of this, the Company is no longer obliged to its Original Agreement. Upon entering the ELA, the Company had an outstanding accounts receivable balance of $306,143, which was forfeited and recognized this amount as deferred contract costs. This amount was offset by $102,217, which was reimbursement from the licensee for project costs on this project. The Company incurred total deferred contract costs of $203,926. The Company considered this amount an incremental cost of obtaining that ELA, because the Company expects to recover those costs through future royalty payments. The Company plans to amortize the asset over sixty months, which is the initial term of the ELA because the asset relates to the services transferred to the customer during the contract term. As of September 30, 2020, accumulated amortization related to deferred contract costs amounted to $40,786. During the three and nine months ended September 30, 2020, amortization expense relating to the deferred contract costs amounted to $10,197 and $30,590, respectively, and is included in general and administrative expenses on the accompanying condensed consolidated statement of operations.

Exclusive License Agreement – On October 3, 2019, as amended on October 17, 2019, the Company entered into the ELA with CPF GP 2019-1 LLC (the “Licensee”), pursuant to which the Company granted the Licensee an exclusive license (the “License”) solely within the United States and its legal territories to the Company’s technology, intellectual property, any improvements thereto, and any related permits, in order to develop and commercialize products within the field of design and project management platforms for residential use, including single-family residences and multi-family residences, but excluding military housing. The Ridge Avenue Project has also been excluded from the License. The License Agreement has an initial term of five (5) years and will automatically renew for subsequent five (5) year periods. The License Agreement provides for customary terminating provisions, including the right by the Company to terminate if the Licensee fails to make minimum royalty payments (as described below).

In consideration for the License, during the initial term, the Licensee agreed to pay the Company a royalty of (x) five percent (5%) on the first $20,000,000 of gross revenues derived from the Licensee’s commercialization of the License (net of customary discounts, sales taxes, delivery charges, and amounts for returns) (the “Gross Revenues”), (y) four and one-half percent (4.5%) on the next $30,000,000 of Gross Revenues, and (z) five percent (5%) on all Gross Revenues thereafter (collectively, the “Royalty”), subject to the following minimum royalty payments determined on a cumulative basis during the initial term: $500,000 in year 1, $750,000 in year 2, $1,500,000 in year 3, $2,000,000 in year 4, and $2,500,000 in year 5. If the License Agreement is extended beyond the initial term, then the parties will negotiate in good faith the royalty rate and the minimum royalty payments for the renewal term(s). In addition, to the extent the Licensee sublicenses any aspect of the License to a sub-licensee, the Licensee will pay to the Company fifty percent (50%) of all payments received by the Licensee from such sublicensee. The Company may also provide the Licensee with professional services with respect to the License, and the Licensee will reimburse the Company for employees’ time, materials, and expenses incurred in providing such professional services. The Licensee also separately agreed to reimburse the Company for any third-party expenses incurred by the Company in developing the Company’s remaining and future residential projects.

The License Agreement provides for customary indemnification obligations between the parties and further provides that the Licensee will indemnify the Company for any claims arising out of the commercialization of the License by the Licensee or any of its subsidiaries, contractors, or sublicensees. In addition, the License Agreement provides that the Company will provide the Licensee with cost estimates for the fabrication and manufacturing of residential projects in the Company’s existing pipeline as of the date of the License Agreement, and if such projects cannot be reasonably constructed and installed at or below such estimates, then the Licensee may withhold payment of any royalty due to the Company under the License Agreement on a dollar-for-dollar basis to offset the costs above the originally estimated amounts.

Business Combinations

Business Combinations - The Company accounts for business acquisitions using the acquisition method of accounting in accordance with ASC 805 “Business Combinations”, which requires recognition and measurement of all identifiable assets acquired and liabilities assumed at their fair value as of the date control is obtained. The Company determines the fair value of assets acquired and liabilities assumed based upon its best estimates of the acquisition-date fair value of assets acquired and liabilities assumed in the acquisition. Goodwill represents the excess of the purchase price over the fair value of the net tangible and identifiable intangible assets acquired. Subsequent adjustments to fair value of any contingent consideration are recorded to the Company’s condensed consolidated statements of operations. Costs that the Company incurs to complete the business combination are charged to general and administrative expenses as they are incurred.

Variable Interest Entities

Variable Interest Entities – The Company accounts for certain legal entities as variable interest entities (“VIE"). When evaluating a VIE for consolidation, the Company must determine whether or not there is a variable interest in the entity. Variable interests are investments or other interests that absorb portions of an entity’s expected losses or receive portions of the entity’s expected returns. If it is determined that the Company does not have a variable interest in the VIE, no further analysis is required and the VIE is not consolidated. If the Company holds a variable interest in a VIE, the Company consolidates the VIE when there is a controlling financial interest in the VIE and therefore are deemed to be the primary beneficiary. The Company is determined to have a controlling financial interest in a VIE when it has both the power to direct the activities of the VIE that most significantly impact the VIE economic performance and the obligation to absorb losses or the right to receive benefits of the VIE that could potentially be significant to that VIE. This determination is evaluated periodically as facts and circumstances change.

On August 27, 2020 the Company entered into a joint venture agreement with Clarity Lab Solutions, LLC (“Clarity Labs”) (the “JV”). In consideration and subject to Clarity Lab’s services and commitments and provided the agreement remains valid and in force, and is not terminated, SGB shall issue 200,000 restricted shares of SGB common stock over a defined vesting period starting in December 1, 2020. Clarity Labs is a licensed clinical laboratory that uses specialized molecular testing equipment and that focuses on the diagnosis and treatment of critical diseases, including COVID-19. Clarity Labs is also engaged in the business of manufacturing, importing and distributions various medical tests. Under the JV, the Company and Clarity Labs will jointly market, sell, and distributed certain products and services (“Clarity Mobile Venture”). As of September 30, 2020, the only activity of Clarity Mobile Venture was a cash transfer from the Company and is included in the condensed consolidated financial statements.

Cash and cash equivalents

Cash and cash equivalents – The Company considers cash and cash equivalents to include all short-term, highly liquid investments that are readily convertible to known amounts of cash and have original maturities of three months or less upon acquisition. Cash and cash equivalents totaled $13,047,565 as of September 30, 2020 and $1,625,671 as of December 31, 2019.

Short-term investment

Short-term investment – The Company classifies investments consisting of a certificate of deposit with a maturity greater than three months but less than one year as short-term investment. The Company had no short-term investment as of September 30, 2020 or December 31, 2019, respectively.

Accounts receivable and allowance for credit losses

Accounts receivable and allowance for credit losses – Accounts receivable are receivables generated from sales to customers and progress billings on performance type contracts. Amounts included in accounts receivable are deemed to be collectible within the Company’s operating cycle. The Company recognizes accounts receivable at invoiced amounts.

The allowance for credit losses reflects the Company's best estimate of expected losses inherent in the accounts receivable balances. Management provides an allowance for credit losses based on the Company’s historical losses, specific customer circumstances, and general economic conditions. Periodically, management reviews accounts receivable and adjusts the allowance based on current circumstances and charges off uncollectible receivables when all attempts to collect have been exhausted and the prospects for recovery are remote. Recoveries are recognized when they are received. Actual collection losses may differ from our estimates and could be material to our condensed consolidated financial position, results of operations, and cash flows.

Inventory

Inventory – Raw construction materials (primarily shipping containers and fabrication materials) are valued at the lower of cost (first-in, first-out method) or net realizable value. Finished goods and work-in-process inventories are valued at the lower of cost or net realizable value, using the specific identification method. Medical equipment and COVID-19 test and testing supplies are valued at the lower of cost, (first-in, first-out method) or net realizable value. As of September 30, 2020 there was inventory of $166,120 for construction materials, and $646,200 of medical equipment and COVID-19 test and testing supplies. There was no inventory for December 31, 2019.

Goodwill

Goodwill – The Company performs its impairment test of goodwill at the reporting unit level each fiscal year, or more frequently if events or circumstances change that would more likely than not reduce the fair value of its reporting unit below its carrying values. The Company performs a goodwill impairment test by comparing the fair value of the reporting unit with its carrying value and recognizes an impairment charge for the amount by which the carrying value exceeds the fair value, not to exceed the total amount of goodwill. The amount by which the carrying value of the goodwill exceeds its implied fair value, if any, is recognized as an impairment loss. The Company’s evaluation of goodwill completed during the year ended December 31, 2019 resulted in impairment loss of $2,938,653, which represents the total goodwill impairment loss to date. The impairment loss was due to a deterioration in the Company's estimated future cash flows. There were no impairments during the nine months ended September 30, 2020. The Company has taken the recent COVID-19 pandemic into consideration when determining impairment.

Intangible assets

Intangible assets – Intangible assets consist of $2,766,000 of proprietary knowledge and technology, which is being amortized over 20 years. In addition, included in intangible assets is $7,928 for non-compete agreements which is being amortized over 5 years, $105,762 of trademarks, and $5,300 of website costs that are being amortized over 5 years and $18,848 of customer contracts over 1 year. The Company evaluated intangible assets for impairment during the year ended December 31, 2019, and determined that there were no impairment losses. There was no impairment during the nine months ended September 30, 2020. The accumulated amortization as of September 30, 2020 and 2019 was $610,157 and $1,578,034, respectively. The amortization expense for the three months ended September 30, 2020 and 2019 was $36,281 and $36,281, respectively. The amortization expense for the nine months ended September 30, 2020 and 2019 was $108,842 and $108,843, respectively. The estimated amortization expense for the successive five years is as follows:

For the year ending December 31,:
2020	$	45,236
2021		176,234
2022		157,775
2023		155,981
2024		155,274
Thereafter		1,603,181
	$	2,293,681

Property, plant and equipment

Property, plant and equipment – Property, plant and equipment is stated at cost. Depreciation is computed using the straight-line method over the estimated lives of each asset. Estimated useful lives for significant classes of assets are as follows: computer and software 3 to 5 years, furniture and other equipment 5 to 7 years, automobiles 2 to 5 years, buildings held for lease 40 years, and equipment 5 to 29 years. Repairs and maintenance are charged to expense when incurred.

Convertible instruments

Convertible instruments – The Company bifurcates conversion options from their host instruments and accounts for them as free standing derivative financial instruments according to certain criteria. The criteria include circumstances in which (a) the economic characteristics and risks of the embedded derivative instrument are not clearly and closely related to the economic characteristics and risks of the host contract, (b) the hybrid instrument that embodies both the embedded derivative instrument and the host contract is not re-measured at fair value under otherwise applicable generally accepted accounting principles with changes in fair value reported in earnings as they occur and (c) a separate instrument with the same terms as the embedded derivative instrument would be considered a derivative instrument.

Common stock purchase warrants and other derivative financial instruments

Common stock purchase warrants and other derivative financial instruments – The Company classifies as equity any contracts that (i) require physical settlement or net-share settlement or (ii) provides a choice of net-cash settlement or settlement in the Company’s own shares (physical settlement or net-share settlement) providing that such contracts are indexed to the Company’s own stock. The Company classifies as assets or liabilities any contracts that (i) require net-cash settlement (including a requirement to net cash settle the contract if any event occurs and if that event is outside the Company’s control) or (ii) gives the counterparty a choice of net-cash settlement or settlement shares (physical settlement or net-cash settlement). The Company assesses classification of common stock purchase warrants and other free standing derivatives at each reporting date to determine whether a change in classification between assets and liabilities or equity is required.

Fair value measurements

Fair value measurements – Financial instruments, including cash and cash equivalents, accounts receivable, accounts payable and accrued liabilities are carried at cost, which the Company believes approximates fair value due to the short-term nature of these instruments.

The Company measures the fair value of financial assets and liabilities based on the exchange price that would be received for an asset or paid to transfer a liability (an exit price) in the principal or most advantageous market for the asset or liability in an orderly transaction between market participants on the measurement date. The Company maximizes the use of observable inputs and minimizes the use of unobservable inputs when measuring fair value.

The Company uses three levels of inputs that may be used to measure fair value:

	Level 1	Quoted prices in active markets for identical assets or liabilities.
	Level 2	Quoted prices for similar assets and liabilities in active markets or inputs that are observable.
	Level 3	Inputs that are unobservable (for example, cash flow modeling inputs based on assumptions).

Financial assets and liabilities measured at fair value on a recurring basis are summarized below as of September 30, 2020:

	Level 3:
	Significant
	unobservable
	inputs		Total
Earnout liability	$	752,559	$	752,559

Transfer into and transfers out of the hierarchy levels are recognized as if they had taken place at the end of the reporting period. There were no transfers into or out of the hierarchy levels during the nine months ended September 30, 2020 or 2019, besides the transfer in of the earnout liability.

Share-based payments

Share-based payments – The Company measures the cost of services received in exchange for an award of equity instruments based on the fair value of the award. For employees and directors, including non-employee directors, the fair value of a stock option award is measured on the grant date. The fair value amount is then recognized over the period services are required to be provided in exchange for the award, usually the vesting period. The Company recognizes stock-based compensation expense on a graded-vesting basis over the requisite service period for each separately vesting tranche of each award. Stock-based compensation expense to employees and all directors are reported within payroll and related expenses in the consolidated statements of operations. Stock-based compensation expense to non-employees is reported within marketing and business development expense in the condensed consolidated statements of operations.

Income taxes

Income taxes – The Company accounts for income taxes utilizing the asset and liability approach. Under this approach, deferred taxes represent the future tax consequences expected to occur when the reported amounts of assets and liabilities are recovered or paid. The provision for income taxes generally represents income taxes paid or payable for the current year plus the change in deferred taxes during the year. Deferred taxes result from the differences between the financial and tax bases of the Company’s assets and liabilities and are adjusted for changes in tax rates and tax laws when changes are enacted.

The calculation of tax liabilities involves dealing with uncertainties in the application of complex tax regulations. The Company recognizes liabilities for anticipated tax audit issues based on the Company’s estimate of whether, and the extent to which, additional taxes will be due. If payment of these amounts ultimately proves to be unnecessary, the reversal of the liabilities would result in tax benefits being recognized in the period when the liabilities are no longer determined to be necessary. If the estimate of tax liabilities proves to be less than the ultimate assessment, a further charge to expense would result.

Concentrations of credit risk

Concentrations of credit risk – Financial instruments, that potentially subject the Company to concentration of credit risk, consist principally of cash and cash equivalents. The Company places its cash with high credit quality institutions. At times, such amounts may be in excess of the FDIC insurance limits. The Company has not experienced any losses in such account and believes that it is not exposed to any significant credit risk on the account.

With respect to receivables, concentrations of credit risk are limited to a few customers in the construction industry. The Company performs ongoing credit evaluations of its customers’ financial condition and, generally, requires no collateral from its customers other than normal lien rights. At September 30, 2020 and December 31, 2019, 92% and 92%, respectively, of the Company’s gross accounts receivable were due from three and one customers.

Revenue relating to four and two customers represented approximately 83% and 94% of the Company’s total revenue for the three months ended September 30, 2020 and 2019, respectively. Revenue relating to three and two customers represented approximately 53% and 87% of the Company's total revenue for the nine months ended September 30, 2020 and 2019, respectively.

Cost of revenue relating to two vendors represented approximately 63% and 93% of the Company's total cost of revenue for the three months ended September 30, 2020 and 2019, respectively. Cost of revenue relating to four vendors represented approximately 67% and 94% of the Company’s total cost of revenue for the nine months ended September 30, 2020 and 2019, respectively. The Company believes it has access to alternative suppliers, with limited disruption to the business, should circumstances change with its existing suppliers.