7. Unpaid losses and loss expenses

Property and casualty

ACE establishes reserves for the estimated unpaid ultimate liability for losses and loss expenses under the terms of its policies and agreements. These reserves include estimates for both claims that have been reported and for IBNR, and include estimates of expenses associated with processing and settling these claims. The process of establishing reserves for P&C claims can be complex and is subject to considerable variability as it requires the use of informed estimates and judgments. Our estimates and judgments may be revised as additional experience and other data become available and are reviewed, as new or improved methodologies are developed, or as current laws change. We continually evaluate our estimate of reserves in light of developing information and in light of discussions and negotiations with our insureds. While we believe that our reserves for unpaid losses and loss expenses at December 31, 2011 are adequate, new information or trends may lead to future developments in ultimate losses and loss expenses significantly greater or less than the reserves provided. Any such revisions could result in future changes in estimates of losses or reinsurance recoverable and would be reflected in our results of operations in the period in which the estimates are changed.

The following table presents a reconciliation of unpaid losses and loss expenses:


	Years Ended December 31
(in millions of U.S. dollars)	2011			2010			2009
Gross unpaid losses and loss expenses, beginning of year	$	37,391		$	37,783		$	37,176
Reinsurance recoverable on unpaid losses⁽¹⁾		(12,149	)		(12,745	)		(12,935	)
Net unpaid losses and loss expenses, beginning of year		25,242			25,038			24,241
Acquisition of subsidiaries		92			145			–
Total		25,334			25,183			24,241
Net losses and loss expenses incurred in respect of losses occurring in:
Current year		10,076			8,082			7,998
Prior years		(556	)		(503	)		(576	)
Total		9,520			7,579			7,422
Net losses and loss expenses paid in respect of losses occurring in:
Current year		4,209			2,689			2,493
Prior years		4,657			4,724			4,455
Total		8,866			7,413			6,948
Foreign currency revaluation and other		(113	)		(107	)		323
Net unpaid losses and loss expenses, end of year		25,875			25,242			25,038
Reinsurance recoverable on unpaid losses⁽¹⁾		11,602			12,149			12,745
Gross unpaid losses and loss expenses, end of year	$	37,477		$	37,391		$	37,783

⁽¹⁾ Net of provision for uncollectible reinsurance.

Net losses and loss expenses incurred includes $556 million, $503 million, and $576 million, of net favorable prior period development in the years ended December 31, 2011, 2010, and 2009, respectively. The following is a summary of prior period development for the periods indicated. The remaining net development for long-tail and short-tail business for each segment comprises numerous favorable and adverse movements across lines and accident years.

Insurance – North American

Insurance – North American's active operations experienced net favorable prior period development of $297 million in 2011, representing 1.9 percent of net unpaid reserves at December 31, 2010. Net prior period development was the net result of several underlying favorable and adverse movements. Net favorable development of $186 million on long-tail business included favorable development of $82 million in the directors and officers (D&O) portfolio affecting the 2006 and prior accident years; $54 million in the excess casualty business affecting the 2005 and prior accident years; $43 million on medical risk operations; $28 million on the national accounts portfolio (commercial auto liability, general liability, and workers' compensation lines of business); and $26 million within the financial solutions business relating to a single account on the 2002 through 2010 accident years. Additional favorable development included $26 million in the foreign casualty product affecting the 2007 and prior accident years; and $21 million on surety business primarily impacting the 2009 year. Partially offsetting this favorable development was adverse development of $40 million on errors and omissions coverage primarily affecting the 2007 and 2008 accident years and adverse development of $29 million within the environmental liability product line concentrated in the 2005 through 2007 accident years. Net prior period development also included adverse development of $25 million on other lines across a number of accident years, none of which was significant. Net favorable development of $111 million on short-tail business included favorable development of $48 million in the property portfolios primarily affecting the 2009 and 2010 accident years and favorable development of $63 million on other lines across a number of accident years, primarily following better than expected loss emergence.

Insurance – North American's runoff operations experienced net adverse prior period development of $102 million in the Westchester and Brandywine runoff operations during 2011, which was the net result of adverse movements impacting the accident years 2000 and prior, representing 0.6 percent of net unpaid reserves at December 31, 2010. Net adverse prior period development was driven by adverse development of $82 million related to the completion of the reserve review during 2011 and $17 million of unallocated loss adjustment expenses due to operating expenses reserved and paid during the current year. Net prior period development also included $3 million of adverse development on other lines across a number of accident years, none of which was significant.

Insurance – North American's active operations experienced net favorable prior period development of $239 million in 2010, representing 1.5 percent of net unpaid reserves at December 31, 2009. Net prior period development was the net result of several underlying favorable and adverse movements. Net favorable development of $102 million on long-tail business included $49 million within the financial solutions business, primarily in the 2000 and prior accident years; favorable development of $105 million in the D&O and E&O portfolios, primarily in the 2006 and prior accident years partially offset by adverse movements in the 2007-2009 years; and favorable development of $54 million on the national accounts portfolio primarily in the 2005, 2006, and 2009 accident years. Partially offsetting this favorable development was adverse development of $91 million in excess casualty businesses principally arising in the 2007 accident year and adverse development of $30 million in small and middle market guaranteed cost workers' compensation portfolios on accident years 2008 and subsequent. Net prior period development also included favorable development of $15 million on other lines across a number of accident years, due primarily to better than expected loss emergence. Net favorable development of $137 million on short-tail business included favorable development of $41 million in the crop/hail business associated with recording the most recent bordereaux for the 2009 and prior crop years and favorable development of $96 million in property, aviation, inland and recreational marine, political risk, and other short-tailed exposures principally in accident years 2007-2009.

Insurance – North American's runoff operations experienced net adverse prior period development of $132 million in 2010, representing 0.8 percent of net unpaid reserves at December 31, 2009. Net prior period development was the net result of several underlying favorable and adverse movements, including adverse development of $114 million in the Westchester and Brandywine runoff operations, impacting accident years 1999 and prior, including $89 million related to the completion of the reserve review during 2010, and adverse development of $18 million on runoff CIS workers' compensation following emergence of higher than expected medical costs impacting accident years 2000 and prior.

Insurance – North American experienced net favorable prior period development of $179 million in 2009, representing 1.2 percent of the segment's net unpaid reserves at December 31, 2008.

Insurance – Overseas General

Insurance – Overseas General experienced net favorable prior period development of $290 million in 2011 representing 4.2 percent of net unpaid reserves at December 31, 2010. Net prior period development was the net result of several underlying favorable and adverse movements. Net favorable development of $154 million on long-tail business included favorable development of $337 million in casualty (primary and excess) and financial lines for accident years 2007 and prior, and adverse development of $183 million in the casualty (primary and excess) and financial lines book for accident years 2008-2010. Net favorable development of $136 million on short-tail business included property, marine, A&H, and energy lines across multiple geographical regions, and within both retail and wholesale operations, principally on accident years 2008-2009.

Insurance – Overseas General experienced net favorable prior period development of $290 million in 2010 representing 4.3 percent of net unpaid reserves at December 31, 2009. Net prior period development was the net result of several underlying favorable and adverse movements. Net favorable development of $159 million on long-tail business included favorable development of $241 million in casualty (primary and excess) and financial lines for accident years 2006 and prior, and adverse development of $82 million in the casualty (primary and excess) and financial lines book for accident years 2007-2009. Net favorable development of $131 million on short-tail business included property, marine, A&H, and energy lines across multiple geographical regions, and within both retail and wholesale operations, principally on accident years 2007-2009.

Insurance – Overseas General experienced net favorable prior period development of $255 million in 2009, representing 4.2 percent of the segment's net unpaid reserves at December 31, 2008.

Global Reinsurance

Global Reinsurance experienced net favorable prior period development of $71 million in 2011 representing 3.1 percent of net unpaid reserves at December 31, 2010. Net prior period development was the net result of several underlying favorable and adverse movements. Net favorable development of $58 million on long-tail business included net favorable development of $79 million principally in treaty years 2007 and prior across a number of portfolios (professional liability, D&O, casualty, and medical malpractice). Net favorable development of $13 million on short-tail business, primarily in treaty years 2009 and prior across property lines, included property catastrophe, trade credit, and surety.

Global Reinsurance experienced net favorable prior period development of $106 million in 2010 representing 4.7 percent of net unpaid reserves at December 31, 2009. Net prior period development was the net result of several underlying favorable and adverse movements. Net favorable development of $72 million on long-tail business included net favorable development of $96 million principally in treaty years 2003-2006 across a number of portfolios (professional liability, D&O, casualty, and medical malpractice). Net favorable development of $34 million on short-tail business, primarily in treaty years 2003-2008 across property lines, included property catastrophe, trade credit, and surety.

Global Reinsurance experienced net favorable prior period development of $142 million in 2009, representing 5.6 percent of the segment's net unpaid reserves at December 31, 2008.

Asbestos and environmental (A&E) and other run-off liabilities

Included in liabilities for losses and loss expenses are amounts for A&E (A&E liabilities). The A&E liabilities principally relate to claims arising from bodily-injury claims related to asbestos products and remediation costs associated with hazardous waste sites. The estimation of A&E liabilities is particularly sensitive to future changes in the legal, social, and economic environment. ACE has not assumed any such future changes in setting the value of its A&E reserves, which include provisions for both reported and IBNR claims.

ACE's exposure to A&E claims principally arises out of liabilities acquired when it purchased Westchester Specialty in 1998 and CIGNA's P&C business in 1999, with the larger exposure contained within the liabilities acquired in the CIGNA transaction. In 1996, prior to ACE's acquisition of CIGNA's P&C business, the Pennsylvania Insurance Commissioner approved a plan to restructure INA Financial Corporation and its subsidiaries (the Restructuring) which included the division of Insurance Company of North America (INA) into two separate corporations:

(1) An active insurance company that retained the INA name and continued to write P&C business; and

(2) An inactive run-off company, now called Century Indemnity Company (Century).

As a result of the division, predominantly all A&E and certain other liabilities of INA were allocated to Century and extinguished, as a matter of Pennsylvania law, as liabilities of INA.

As part of the Restructuring, most A&E liabilities of various U.S. affiliates of INA were reinsured to Century. Century and certain other run-off companies having A&E and other liabilities were contributed to Brandywine Holdings. ACE acquired Brandywine Holdings and its various subsidiaries as part of the 1999 acquisition of CIGNA's P&C business. For more information, refer to "Brandywine Run-Off Entities" below.

During 2011, we conducted our annual internal, ground-up review of our consolidated A&E liabilities as of December 31, 2010. As a result of the internal review, we increased our net loss reserves in 2011 for the Brandywine operations, including A&E, by $76 million, while the gross loss reserves increased by $241 million. In addition, we decreased gross loss reserves for Westchester Specialty's A&E and other liabilities by $29 million, while the net loss reserves increased by $6 million. An internal review was also conducted during 2010 of consolidated A&E liabilities as of December 31, 2009. As a result of that internal review, we increased net loss reserves in 2010 for the Brandywine operations, including A&E, by $84 million, while the gross loss reserves increased by $247 million.

In 2010, in addition to our annual internal review, a team of external actuaries performed an evaluation as to the adequacy of Century's reserves. This external review was conducted in accordance with the Brandywine Restructuring Order, which requires that an independent actuarial review of Century's reserves be completed every two years. Management takes full responsibility for the estimation of its A&E liabilities. The difference between the conclusions of the internal and external reviews is an immaterial amount to reserves on a net basis after giving effect to the reserve increases for the Brandywine operations described above.

ACE's A&E reserves are not discounted for GAAP reporting and do not reflect any anticipated future changes in the legal, social, or economic environment, or any benefit from future legislative reforms.

The table below presents a roll-forward of consolidated A&E loss reserves (excluding other run-off liabilities), allocated loss expense reserves for A&E exposures, and the provision for uncollectible paid and unpaid reinsurance recoverables:


	Asbestos						Environmental						Total
(in millions of U.S. dollars)	Gross			Net			Gross			Net			Gross			Net
Balance at December 31, 2010	$	2,130		$	1,120		$	316		$	215		$	2,446		$	1,335
Incurred activity		148			67			66			37			214			104
Payment activity		(311	)		(168	)		(99	)		(75	)		(410	)		(243	)
Balance at December 31, 2011	$	1,967		$	1,019		$	283		$	177		$	2,250		$	1,196

The A&E net loss reserves including allocated loss expense reserves and provision for uncollectible reinsurance at December 31, 2011, of $1.2 billion shown in the table above comprise $909 million in reserves in respect of Brandywine operations, $143 million of reserves held by Westchester Specialty, $61 million of reserves held by ACE Bermuda, and $83 million of reserves held by Insurance – Overseas General. The incurred activity of $104 million is the result of adverse activity in Brandywine and Westchester of $59 million and $48 million, respectively, offset by favorable activity in Insurance – Overseas General of $3 million on the provision for uncollectible reinsurance.

The net figures in the above table reflect third-party reinsurance other than reinsurance provided by NICO under two aggregate excess of loss contracts described below (collectively, the NICO contracts). ACE excludes the NICO contracts as they cover non-A&E liabilities as well as A&E liabilities. The split of coverage provided under the NICO contracts for A&E liabilities as compared to non-A&E liabilities is entirely dependent on the timing of the payment of the related claims. ACE's ability to make an estimate of this split is not practicable. ACE believes, instead, that the A&E discussion is best provided excluding the NICO contracts, while separately discussing the NICO contracts in relation to the total subject business, both A&E and non-A&E, covered by those contracts. With certain exceptions, the NICO contracts provide coverage for the net A&E incurred losses and allocated loss expenses within the limits of coverage and above ACE's retention levels. These exceptions include losses arising from certain operations of Insurance – Overseas General and participation by ACE Bermuda as a co-reinsurer or retrocessionaire in the NICO contracts.

Brandywine run-off – impact of NICO contracts on ACE's run-off liabilities

As part of the acquisition of CIGNA's P&C business, NICO provided $2.5 billion of reinsurance protection to Century on all Brandywine loss and allocated loss adjustment expense reserves and on the A&E reserves of various ACE INA insurance subsidiaries reinsured by Century (in each case, including uncollectible reinsurance). The benefits of this NICO contract (the Brandywine NICO Agreement) flow to the other Brandywine companies and to the ACE INA insurance subsidiaries through agreements between those companies and Century. The Brandywine NICO Agreement was exhausted on an incurred basis in the fourth quarter of 2002.

The following table presents a roll-forward of net loss reserves, allocated loss expense reserves, and provision for uncollectible paid and unpaid reinsurance recoverables in respect of Brandywine operations only, including the impact of the Brandywine NICO Agreement for the year ended December 31, 2011:


	Brandywine									NICO Coverage			Net of NICO Coverage
(in millions of U.S. dollars)	A&E			Other⁽¹⁾			Total			NICO Coverage			Net of NICO Coverage
Balance at December 31, 2010	$	1,044		$	881		$	1,925		$	928		$	997
Incurred activity		59			9			68			–			68
Paid activity		(194	)		(98	)		(292	)		(304	)		12
Balance at December 31, 2011	$	909		$	792		$	1,701		$	624		$	1,077

⁽¹⁾ Other consists primarily of workers' compensation, non-A&E general liability losses, and provision for uncollectible reinsurance on non-A&E business.

The incurred activity of $68 million primarily relates to the internal review of consolidated A&E liabilities as discussed above.

Westchester Specialty – impact of NICO contracts on ACE's run-off liabilities

As part of the Westchester Specialty acquisition in 1998, NICO provided a 75 percent pro-rata share of $1 billion of reinsurance protection on losses and loss adjustment expenses incurred on or before December 31, 1996, in excess of a retention of $721 million (the 1998 NICO Agreement). NICO has also provided an 85 percent pro-rata share of $150 million of reinsurance protection on losses and allocated loss adjustment expenses incurred on or before December 31, 1992, in excess of a retention of $755 million (the 1992 NICO Agreement). At December 31, 2011, the remaining unused incurred limit under the 1998 NICO Agreement was $504 million, which is only available for losses and loss adjustment expenses. The 1992 NICO Agreement was exhausted on a paid basis in 2009.

The following table presents a roll-forward of net loss reserves, allocated loss expense reserves, and provision for uncollectible paid and unpaid reinsurance recoverables in respect of 1996 and prior Westchester Specialty operations that are the subject business of the NICO covers for the year ended December 31, 2011:


	Westchester Specialty									NICO Coverage			Net of NICO Coverage
(in millions of U.S. dollars)	A&E			Other			Total			NICO Coverage			Net of NICO Coverage
Balance at December 31, 2010	$	122		$	87		$	209		$	186		$	23
Incurred activity		48			(29	)		19			14			5
Paid activity		(27	)		(4	)		(31	)		(35	)		4
Balance at December 31, 2011	$	143		$	54		$	197		$	165		$	32

Brandywine run-off entities

In addition to housing a significant portion of ACE's A&E exposure, the Brandywine operations include run-off liabilities related to various insurance and reinsurance businesses. ACE's Brandywine operations comprise Century (a Pennsylvania insurer) and Century International Reinsurance Company Ltd., a Bermuda insurer (CIRC). The Brandywine companies are direct or indirect subsidiaries of Brandywine Holdings.

During the three months ended June 30, 2010, in order to better align assets and liabilities, Brandywine Holdings Corporation transferred its ownership of CIRC stock to Century. Thus, Century (which reinsures substantially all of CIRC's liabilities) became the direct parent of CIRC and Century's statutory surplus rose above the $25 million required by the 1996 Pennsylvania Insurance Department Restructuring Order. The realignment of CIRC as a subsidiary of Century increased Century's surplus and strengthened its ability to meet its future obligations, including its obligations as a reinsurer of the ACE active companies. The transfer of CIRC stock increased Century's assets by $169 million and resulted in (a) the elimination of Century's reserve cession to the aggregate excess of loss agreement, described below (the XOL) and (b) an increase in Century's surplus by $26 million to $51 million as of June 30, 2010. Century's increased statutory surplus position allowed it to satisfy certain balances payable to ACE active companies under another affiliate reinsurance agreement. Due to a contractual provision, these balances were prohibited from being paid to ACE active companies while Century was ceding statutory reserves under the XOL.

The U.S.-based ACE INA companies assumed two contractual obligations in respect of the Brandywine operations in connection with the Restructuring: a dividend retention fund obligation and a surplus maintenance obligation in the form of the XOL.

INA Financial Corporation established and funded a dividend retention fund (the Dividend Retention Fund) consisting of $50 million plus investment earnings. Pursuant to an interpretation of the Brandywine Restructuring Order, the full balance of the Dividend Retention Fund was contributed to Century as of December 31, 2002. Under the Restructuring Order, while any obligation to maintain the Dividend Retention Fund is in effect, to the extent dividends are paid by INA Holdings Corporation to its parent, INA Financial Corporation, and to the extent INA Financial Corporation then pays such dividends to INA Corporation, a portion of those dividends must be withheld to replenish the principal of the Dividend Retention Fund to $50 million. During 2011 and 2010, $35 million and $15 million, respectively, were withheld from such dividends and deposited in the Dividend Retention Fund by INA Financial Corporation. Effective January 28, 2011, the Pennsylvania Insurance Department clarified the scope of the Dividend Retention Fund that capital contributions from the Dividend Retention Fund to Century shall not be required until the XOL Agreement has less than $200 million of capacity remaining on an incurred basis for statutory reporting purposes. The amount of the capital contribution shall be the lesser of the amount necessary to restore the XOL Agreement capacity to $200 million or the Dividend Retention Fund balance. The Dividend Retention Fund may not be terminated without prior written approval from the Pennsylvania Insurance Commissioner.

In addition, an ACE INA insurance subsidiary provided reinsurance coverage to Century in the amount of $800 million under an XOL, triggered if the statutory capital and surplus of Century falls below $25 million or if Century lacks liquid assets with which to pay claims as they become due.

Effective December 31, 2004, ACE INA Holdings contributed $100 million to Century in exchange for a surplus note. After giving effect to the contribution and issuance of the surplus note, the statutory surplus of Century at December 31, 2011 was $25 million and approximately $146 million in statutory-basis losses have been ceded to the XOL on an inception-to-date basis. Century reports the amount ceded under the XOL in accordance with statutory accounting principles, which differ from GAAP by, among other things, allowing Century to discount its liabilities, including certain asbestos related and environmental pollution liabilities. For GAAP reporting purposes, intercompany reinsurance recoverables related to the XOL are eliminated upon consolidation. To estimate ACE's remaining claim exposure under the XOL on an undiscounted basis, ACE adjusts the statutory cession to exclude the discount embedded in statutory loss reserves. At December 31, 2011, approximately $440 million in undiscounted losses were ceded under the XOL, leaving a remaining limit of coverage under that agreement of approximately $360 million. At December 31, 2010, the remaining limit of coverage under the agreement was $410 million on an undiscounted basis.

While ACE believes it has no legal obligation to fund losses above the XOL limit of coverage, ACE's consolidated results would nevertheless continue to include any losses above the limit of coverage for so long as the Brandywine companies remain consolidated subsidiaries of ACE.

Uncertainties relating to ACE's ultimate Brandywine exposure

In addition to the Dividend Retention Fund and XOL commitments described above, certain ACE entities are primarily liable for asbestos, environmental, and other exposures that they have reinsured to Century. Accordingly, if Century were to become insolvent and ACE were to lose control of Century, some or all of the recoverables due to these ACE companies from Century could become uncollectible, yet those ACE entities would continue to be responsible to pay claims to their insureds or reinsureds. At December 31, 2011 and 2010, the aggregate reinsurance balances ceded by the active ACE companies to Century were approximately $877 million and $881 million, respectively. At December 31, 2011 and 2010, Century's carried gross reserves (including reserves ceded by the active ACE companies to Century) were $2.4 billion and $2.7 billion, respectively. ACE believes the intercompany reinsurance recoverables, which relate to liabilities payable over many years (i.e., 25 years or more), are not impaired. A substantial portion of the liabilities ceded to Century by its affiliates have, in turn, been ceded by Century to NICO and, at December 31, 2011 and 2010, remaining cover on a paid loss basis was approximately $624 million and $928 million, respectively. Should Century's loss reserves experience adverse development in the future and should Century be placed into rehabilitation or liquidation, the reinsurance recoverables due from Century to its affiliates would be payable only after the payment in full of certain expenses and liabilities, including administrative expenses and direct policy liabilities. Thus, the intercompany reinsurance recoverables would be at risk to the extent of the shortage of assets remaining to pay these recoverables. Losses ceded by Century to the active ACE companies and other amounts owed to Century by the active ACE companies were, in the aggregate, approximately $526 million and $453 million at December 31, 2011 and 2010, respectively.