FAIR VALUE MEASUREMENTS | 5 . Fair Value Measurements Fair Value Measurements on a Recurring Basis Assets and liabilities recorded at fair value in the Condensed Consolidated Balance Sheet s are measured and classified in accordance with a fair value hierarchy consisting of three “levels” based on the observability of valuation inputs: Level 1: Fair value measurements based on quoted prices (unadjusted) in active markets that we have the ability to access for identical assets or liabilities. Market price data generally is obtained from exchange or dealer markets. We do not adjust the quoted price for such instruments. Level 2: Fair value measurements based on inputs other than quoted prices included in Level 1 that are observable for the asset or liability, either directly or indirectly. Level 2 inputs include quoted prices for similar assets and liabilities in active markets, quoted prices for identical or similar assets or liabilities in markets that are not active, and inputs other than quoted prices that are observable for the asset or liability, such as interest rates and yield curves that are observable at commonly quoted intervals. Le vel 3: Fair value measurements based on valuation techniques that use significant inputs that are unobservable. Both observable and unobservable inputs may be used to determine the fair values of positions classified in Level 3. The circumstances for using these measurements include those in which there is little, if any, market activity for the asset or liability. Therefore, we must make certain assumptions about the inputs a hypothetical market participant would use to value that asset or liability. In certain cases, the inputs used to measure fair value may fall into different leve ls of the fair value hierarchy. In such cases, the level in the fair value hierarchy within which the fair value measurement in its entirety falls is determined based on the lowest level input that is significant to the fair value measurement in its entirety. Assets and Liabilities Measured at Fair Value on a Recurring Basis The following table presents information about assets and liabilities measured at fair value on a recurring basis and indicates the level of the fair value measurement based on the observability of the inputs used: March 31, 2019 Counterparty Cash (in millions) Level 1 Level 2 Level 3 Netting (a) Collateral Total Assets: Bonds available for sale: U.S. government and government sponsored entities $ - $ 3,401 $ - $ - $ - $ 3,401 Obligations of states, municipalities and political subdivisions - 13,786 2,136 - - 15,922 Non-U.S. governments 15 15,256 3 - - 15,274 Corporate debt - 137,141 1,532 - - 138,673 RMBS - 19,959 14,045 - - 34,004 CMBS - 12,269 892 - - 13,161 CDO/ABS - 8,926 8,840 - - 17,766 Total bonds available for sale 15 210,738 27,448 - - 238,201 Other bond securities: U.S. government and government sponsored entities 84 2,696 - - - 2,780 Non-U.S. governments - 51 - - - 51 Corporate debt - 1,745 - - - 1,745 RMBS - 491 1,266 - - 1,757 CMBS - 315 84 - - 399 CDO/ABS - 530 4,249 - - 4,779 Total other bond securities 84 5,828 5,599 - - 11,511 Equity securities 804 11 26 - - 841 Other invested assets (b) - 86 591 - - 677 Derivative assets: Interest rate contracts 4 2,660 - - - 2,664 Foreign exchange contracts - 1,106 1 - - 1,107 Equity contracts 55 330 103 - - 488 Credit contracts - - 1 - - 1 Other contracts - - 13 - - 13 Counterparty netting and cash collateral - - - (1,647) (1,734) (3,381) Total derivative assets 59 4,096 118 (1,647) (1,734) 892 Short-term investments 1,993 2,047 - - - 4,040 Separate account assets 84,260 4,558 - - - 88,818 Other assets - - 59 - - 59 Total $ 87,215 $ 227,364 $ 33,841 $ (1,647) $ (1,734) $ 345,039 Liabilities: Policyholder contract deposits $ - $ - $ 4,878 $ - $ - $ 4,878 Derivative liabilities: Interest rate contracts - 1,905 15 - - 1,920 Foreign exchange contracts - 850 - - - 850 Equity contracts 12 32 7 - - 51 Credit contracts - 17 223 - - 240 Other contracts - - 5 - - 5 Counterparty netting and cash collateral - - - (1,647) (188) (1,835) Total derivative liabilities 12 2,804 250 (1,647) (188) 1,231 Long-term debt - 2,263 - - - 2,263 Other liabilities 105 85 - - - 190 Total $ 117 $ 5,152 $ 5,128 $ (1,647) $ (188) $ 8,562 December 31, 2018 Counterparty Cash (in millions) Level 1 Level 2 Level 3 Netting (a) Collateral Total Assets: Bonds available for sale: U.S. government and government sponsored entities $ 53 $ 3,207 $ - $ - $ - $ 3,260 Obligations of states, municipalities and political subdivisions - 14,001 2,000 - - 16,001 Non-U.S. governments 69 14,445 11 - - 14,525 Corporate debt - 129,836 864 - - 130,700 RMBS - 20,178 14,199 - - 34,377 CMBS - 11,784 917 - - 12,701 CDO/ABS - 8,725 9,102 - - 17,827 Total bonds available for sale 122 202,176 27,093 - - 229,391 Other bond securities: U.S. government and government sponsored entities 11 2,654 - - - 2,665 Non-U.S. governments - 45 - - - 45 Corporate debt - 1,671 - - - 1,671 RMBS - 424 1,290 - - 1,714 CMBS - 311 77 - - 388 CDO/ABS - 454 4,478 - - 4,932 Total other bond securities 11 5,559 5,845 - - 11,415 Equity securities 1,213 13 27 - - 1,253 Other invested assets (b) - 341 587 - - 928 Derivative assets: Interest rate contracts 2 2,888 - - - 2,890 Foreign exchange contracts - 1,159 5 - - 1,164 Equity contracts 133 190 75 - - 398 Credit contracts - - 1 - - 1 Other contracts - - 15 - - 15 Counterparty netting and cash collateral - - - (1,713) (1,840) (3,553) Total derivative assets 135 4,237 96 (1,713) (1,840) 915 Short-term investments 2,416 599 - - - 3,015 Separate account assets 77,202 4,645 - - - 81,847 Other assets - - 58 - - 58 Total $ 81,099 $ 217,570 $ 33,706 $ (1,713) $ (1,840) $ 328,822 Liabilities: Policyholder contract deposits $ - $ - $ 4,116 $ - $ - $ 4,116 Derivative liabilities: Interest rate contracts 4 2,004 15 - - 2,023 Foreign exchange contracts - 858 - - - 858 Equity contracts 12 3 - - - 15 Credit contracts - 8 228 - - 236 Other contracts - - 6 - - 6 Counterparty netting and cash collateral - - - (1,713) (187) (1,900) Total derivative liabilities 16 2,873 249 (1,713) (187) 1,238 Long-term debt - 2,213 - - - 2,213 Other liabilities 16 11 - - - 27 Total $ 32 $ 5,097 $ 4,365 $ (1,713) $ (187) $ 7,594 (a) Represents netting of derivative exposures covered by qualifying master netting agreements. (b) Excludes investments that are measured at fair value using the net asset value (NAV) per share (or its equ ivalent), which totaled $ 5.1 billion and $ 5.0 billion as of March 31, 2019 and December 31, 2018 , respectively. Transfers of Level 1 and Level 2 Assets and Liabilities Our policy is to record transfers of assets and liabilities between L evel 1 and Level 2 at their fair values as of the end of each reporting period, consistent with the date of the determination of fair value. Assets are transferred out of Level 1 when they are no longer transacted with sufficient frequency and volume in an active market. Conversely, assets are transferred from Level 2 to Level 1 when transaction volume and frequency are indicative of an active market. During the three -month periods ended March 31, 2019 and 2018 , we tra nsferred $ 62 million and $ 16 million, respectively, of securities issued by non-U.S. government entities from Level 1 to Level 2, because they are no longer considered actively traded. For similar reasons, during the three -month periods ended March 31, 2019 and 2018 , we transferred $ 51 million and $ 191 million, respectively, of securities issued by the U.S. government and government sponsored entitie s from Level 1 to Level 2. We had no material transfers from Level 2 to Level 1 during the three -month periods ended March 31, 2019 and 2018 . Changes in Level 3 Recurring Fair Value Measurements The following tables p resent changes during the three -month periods ended March 31, 2019 and 2018 in Level 3 assets and liabilities measured at fair value on a recurring basis, and the realized and unrealized gains (losses) related to the L evel 3 assets and liabilities in the Condensed Consolidated Balance Sheets at March 31, 2019 and 2018 : Net Changes in Realized and Purchases, Unrealized Gains Unrealized Sales, (Losses) Included Fair Value Gains (Losses) Other Issuances and Gross Gross Fair Value in Income on Beginning Included Comprehensive Settlements, Transfers Transfers End Instruments Held (in millions) of Period in Income Income (Loss) Net In Out of Period at End of Period Three Months Ended March 31, 2019 Assets: Bonds available for sale: Obligations of states, municipalities and political subdivisions $ 2,000 $ (1) $ 97 $ 24 $ 29 $ (13) $ 2,136 $ - Non-U.S. governments 11 - - (4) - (4) 3 - Corporate debt 864 (3) 38 34 654 (55) 1,532 - RMBS 14,199 227 24 (412) 23 (16) 14,045 - CMBS 917 1 17 146 - (189) 892 - CDO/ABS 9,102 4 54 (45) 92 (367) 8,840 - Total bonds available for sale 27,093 228 230 (257) 798 (644) 27,448 - Other bond securities: Corporate debt - - - - - - - - RMBS 1,290 17 - (41) - - 1,266 - CMBS 77 4 - 3 - - 84 3 CDO/ABS 4,478 68 - (201) - (96) 4,249 24 Total other bond securities 5,845 89 - (239) - (96) 5,599 27 Equity securities 27 - - - - (1) 26 - Mortgage and other loans receivable - - - - - - - - Other invested assets 587 - - 4 - - 591 2 Other assets 58 - - 1 - - 59 - Total $ 33,610 $ 317 $ 230 $ (491) $ 798 $ (741) $ 33,723 $ 29 Net Changes in Realized and Purchases, Unrealized Gains Unrealized Sales, (Losses) Included Fair Value (Gains) Losses Other Issuances and Gross Gross Fair Value in Income on Beginning Included Comprehensive Settlements, Transfers Transfers End Instruments Held (in millions) of Period in Income Income (Loss) Net In Out of Period at End of Period Liabilities: Policyholder contract deposits $ 4,116 $ 569 $ - $ 193 $ - $ - $ 4,878 $ (521) Derivative liabilities, net: Interest rate contracts 15 1 - (1) - - 15 (1) Foreign exchange contracts (5) (5) - 9 - - (1) (1) Equity contracts (75) (16) - (5) - - (96) 19 Credit contracts 227 (3) - (2) - - 222 4 Other contracts (9) (17) - 18 - - (8) 17 Total derivative liabilities, net (a) 153 (40) - 19 - - 132 38 Total $ 4,269 $ 529 $ - $ 212 $ - $ - $ 5,010 $ (483) Net Changes in Realized and Purchases, Unrealized Gains Unrealized Sales, (Losses) Included Fair Value Gains (Losses) Other Issuances and Gross Gross Fair Value in Income on Beginning Included Comprehensive Settlements, Transfers Transfers End Instruments Held (in millions) of Period in Income Income (Loss) Net In Out of Period at End of Period Three Months Ended March 31, 2018 Assets: Bonds available for sale: Obligations of states, municipalities and political subdivisions $ 2,404 $ 1 $ (75) $ (69) $ - $ - $ 2,261 $ - Non-U.S. governments 8 (4) 4 1 - - 9 - Corporate debt 1,173 (57) 10 248 565 (68) 1,871 - RMBS 16,136 266 5 (536) - (32) 15,839 - CMBS 624 6 (17) (23) - (6) 584 - CDO/ABS 8,651 8 (88) (710) - (15) 7,846 - Total bonds available for sale 28,996 220 (161) (1,089) 565 (121) 28,410 - Other bond securities: Corporate debt 18 1 - - - - 19 - RMBS 1,464 39 - (76) - - 1,427 51 CMBS 74 (1) - (1) 1 - 73 (1) CDO/ABS 4,956 89 - (260) - (9) 4,776 8 Total other bond securities 6,512 128 - (337) 1 (9) 6,295 58 Equity securities - - - 3 - - 3 2 Mortgage and other loans receivable 5 - - (5) - - - - Other invested assets 250 23 1 18 - - 292 30 Other assets - - - - - - - - Total $ 35,763 $ 371 $ (160) $ (1,410) $ 566 $ (130) $ 35,000 $ 90 Net Changes in Realized and Purchases, Unrealized Gains Unrealized Sales, (Losses) Included Fair Value (Gains) Losses Other Issuances and Gross Gross Fair Value in Income on Beginning Included Comprehensive Settlements, Transfers Transfers End Instruments Held (in millions) of Period in Income Income (Loss) Net In Out of Period at End of Period Liabilities: Policyholder contract deposits $ 4,136 $ (506) $ - $ 66 $ - $ - $ 3,696 $ 604 Derivative liabilities, net: Interest rate contracts 22 (3) - (2) - - 17 3 Foreign exchange contracts - (10) - 11 - - 1 3 Equity contracts (82) 4 - - - - (78) (4) Credit contracts 262 (10) - (2) - - 250 10 Other contracts (15) (17) - 20 - - (12) 17 Total derivative liabilities, net (a) 187 (36) - 27 - - 178 29 Total $ 4,323 $ (542) $ - $ 93 $ - $ - $ 3,874 $ 633 (a ) Total Level 3 derivative exposures have been netted in these tables for presentation purposes only. Net realized and unrealized gains and losses included in income related to Level 3 assets and liabilities shown above are reported in the Condensed Consolidated Statements of Income as follows: Net Net Realized Investment Capital Other (in millions) Income Gains (Losses) Income Total Three Months Ended March 31, 2019 Assets: Bonds available for sale $ 242 $ (14) $ - $ 228 Other bond securities 87 2 - 89 Other invested assets - - - - Three Months Ended March 31, 2018 Assets: Bonds available for sale $ 282 $ (62) $ - $ 220 Other bond securities 23 (4) 109 128 Other invested assets 25 - (2) 23 Net Net Realized Investment Capital Other (in millions) Income (Gains) Losses Income Total Three Months Ended March 31, 2019 Liabilities: Policyholder contract deposits $ - $ 569 $ - $ 569 Derivative liabilities, net - (24) (16) (40) Three Months Ended March 31, 2018 Liabilities: Policyholder contract deposits $ - $ (506) $ - $ (506) Derivative liabilities, net - 1 (37) (36) The following table presents the gross compo nents of purchases, sales, issuance s and settlements, net, shown a bove, for the three - month periods ended March 31, 2019 and 2018 related to Level 3 assets and liabilities in the Condensed Consolidated Balance Sheets: Issuances Purchases, Sales, and Issuances and (in millions) Purchases Sales Settlements (a) Settlements, Net (a) Three Months Ended March 31, 2019 Assets: Bonds available for sale: Obligations of states, municipalities and political subdivisions $ 47 $ (15) $ (8) $ 24 Non-U.S. governments - - (4) (4) Corporate debt 49 - (15) 34 RMBS 307 (26) (693) (412) CMBS 184 - (38) 146 CDO/ABS 198 (156) (87) (45) Total bonds available for sale 785 (197) (845) (257) Other bond securities: RMBS - - (41) (41) CMBS 4 - (1) 3 CDO/ABS - - (201) (201) Total other bond securities 4 - (243) (239) Equity securities - - - - Mortgage and other loans receivable - - - - Other invested assets 4 - - 4 Other assets - - 1 1 Total assets $ 793 $ (197) $ (1,087) $ (491) Liabilities: Policyholder contract deposits $ - $ 173 $ 20 $ 193 Derivative liabilities, net (13) - 32 19 Total liabilities $ (13) $ 173 $ 52 $ 212 Three Months Ended March 31, 2018 Assets: Bonds available for sale: Obligations of states, municipalities and political subdivisions $ 15 $ - $ (84) $ (69) Non-U.S. governments 2 - (1) 1 Corporate debt 254 (3) (3) 248 RMBS 233 (5) (764) (536) CMBS 12 - (35) (23) CDO/ABS 495 (851) (354) (710) Total bonds available for sale 1,011 (859) (1,241) (1,089) Other bond securities: RMBS 1 (5) (72) (76) CMBS - - (1) (1) CDO/ABS - (4) (256) (260) Total other bond securities 1 (9) (329) (337) Equity securities 3 - - 3 Mortgage and other loans receivable - (5) - (5) Other invested assets 22 - (4) 18 Total assets $ 1,037 $ (873) $ (1,574) $ (1,410) Liabilities: Policyholder contract deposits $ - $ 112 $ (46) $ 66 Derivative liabilities, net (7) - 34 27 Total liabilities $ (7) $ 112 $ (12) $ 93 (a) There were no issuances during the three -month period s ended March 31, 2019 and 2018 , respectively . Both observable and unobservable inputs may be used to determine the fair values of positions classified in Level 3 in the tables above. As a result, the unrealized gains (losses) on instruments held at March 31, 2019 and 2018 may include changes in fair value that were attribut able to both observable (e.g., changes in market interest rates) and unobservable inputs (e.g., changes in unobservable long-dated volatilities) . Transfers of Level 3 Assets and Liabilities We record transfers of assets and liabilities into or out of Level 3 classification at their fair values as of the end of each reporting period, consistent with the date of the determination of fair value. The Net realized and unrealized gains (losses) included in i ncome or Other comprehensive income (loss) as shown in t he table above exclud es $ 55 million and $ 24 million of net losses related to assets and liabilities transferred into Level 3 during the three - month period s ended March 31, 2019 and 2018 , respectively, and include s $ 1 million of net losses related to assets and liabilities transferred out of Level 3 in the three -month period ended March 31, 2019 . Transfers of Level 3 Assets During the three -month periods ended March 31, 2019 and 2018 , transfers into Level 3 assets primarily included certain investments in private placement corporate debt, RMBS, CMBS and CDO/ABS . Transfers of private placement corporate debt and certain ABS into Level 3 assets were primarily the result of limited market pricing information that required us to determine fair value for these securities based on inputs that are adjusted to better reflect our own assumptions regarding the ch aracteristics of a specific security or associated market liquidity . The transfers of investments in RMBS, CMBS and CDO and certain ABS into Level 3 assets were due to decreases in market transparency and liquidity for individual security types. During th e three -month periods ended March 31, 2019 and 2018 , transfers out of Level 3 assets primarily included private placement and other corporate debt, CMBS, RMBS, CDO/ABS and certain investments in municipal securities . Transfers of certain investments in municipal securities, corporate debt, RMBS, CMBS and CDO/ABS out of Level 3 assets were based on consideration of market liquidity as well as related transparency of pricing and associated observable inputs for these inv estments. Transfers of certain investments in private placement corporate debt and certain ABS out of Level 3 assets were primarily the result of using observable pricing information that reflects the fair value of those securities without the need for adj ustment based on our own assumptions regarding the characteristics of a specific security or the current liquidity in the market. Transfers of Level 3 Liabilities There were no significant transfers of derivative or other liabilities into or out of Level 3 for the three -month periods ended March 31, 2019 and 2018 . QUANTITATIVE INFORMATION ABOUT LEVEL 3 FAIR VALUE MEASUREMENTS The table below presents information about the significant unobservable inputs used for recurring fair value measurements for certain Level 3 instruments, and includes only those instruments for which information about the inputs is reasonably available to us , such as data from independent third-party valuation service providers and from internal valuation models. Because input information from third-parties with respect to certain Level 3 in struments (primarily CDO/ABS) may not be reasonably available to us , balances shown below may not equal total amounts reported for such Level 3 assets and liabilities: Fair Value at March 31, Valuation Range (in millions) 2019 Technique Unobservable Input (b) (Weighted Average) Assets: Obligations of states, municipalities and political subdivisions $ 1,590 Discounted cash flow Yield 3.59% - 4.58% (4.08%) Corporate debt 530 Discounted cash flow Yield 4.23% - 6.09% (5.16%) RMBS (a) 13,243 Discounted cash flow Constant prepayment rate 3.63% - 12.64% (8.13%) Loss severity 38.94% - 75.51% (57.22%) Constant default rate 2.17% - 7.14% (4.65%) Yield 2.96% - 5.07% (4.01%) CDO/ABS (a) 4,554 Discounted cash flow Yield 3.45% - 5.21% (4.33%) CMBS 484 Discounted cash flow Yield 2.81% - 5.81% (4.31%) Liabilities: Embedded derivatives within Policyholder contract deposits: Guaranteed minimum withdrawal benefits (GMWB) 2,023 Discounted cash flow Equity volatility 5.85% - 46.25% Base lapse rate 0.16% - 12.60% Dynamic lapse multiplier 20.00% - 180.00% Mortality multiplier (c) 40.00% - 153.00% Utilization 90.00% - 100.00% Equity / interest-rate correlation 20.00% - 40.00% Index Annuities 2,382 Discounted cash flow Lapse rate 0.50% - 40.00% Mortality multiplier (c) 42.00% - 162.00% Option Budget 1.00% - 4.00% Indexed Life 448 Discounted cash flow Base lapse rate 0.00% - 13.00% Mortality rate 0.00% - 100.00% Fair Value at December 31, Valuation Range (in millions) 2018 Technique Unobservable Input (b) (Weighted Average) Assets: Obligations of states, municipalities and political subdivisions $ 1,473 Discounted cash flow Yield 3.91% - 5.00% (4.46%) Corporate debt 445 Discounted cash flow Yield 4.35% - 5.99% (5.17%) RMBS (a) 13,608 Discounted cash flow Constant prepayment rate 4.58% - 14.00% (9.29%) Loss severity 39.66% - 74.40% (57.03%) Constant default rate 2.46% - 7.39% (4.92%) Yield 3.31% - 5.50% (4.40%) CDO/ABS (a) 5,461 Discounted cash flow Yield 3.65% - 5.10% (4.37%) CMBS 447 Discounted cash flow Yield 3.29% - 6.07% (4.68%) Liabilities: Embedded derivatives within Policyholder contract deposits: GMWB 1,943 Discounted cash flow Equity volatility 6.05% - 47.65% Base lapse rate 0.16% - 12.60% Dynamic lapse multiplier 20.00% - 180.00% Mortality multiplier (c) 40.00% - 153.00% Utilization 90.00% - 100.00% Equity / interest-rate correlation 20.00% - 40.00% Index Annuities 1,778 Discounted cash flow Lapse rate 0.50% - 40.00% Mortality multiplier (c) 42.00% - 162.00% Option Budget 1.00% - 3.00% Indexed Life 374 Discounted cash flow Base lapse rate 0.00% - 13.00% Mortality rate 0.00% - 100.00% (a) Information received from third-party valuation service providers. The ranges of the unobservable inputs for constant prepayment rate, loss severity and constant default rate relate to each of the individual underlying mortgage loans that comprise the entire portfolio of securities in the RMBS and CDO securitization vehicles and not necessarily to the securitization vehicle bonds (tranches) purchased by us. The ranges of these inputs do not directly correlate to changes in the fair values of the tra nches purchased by us, because there are other factors relevant to the fair values of specific tranches owned by us including, but not limited to, purchase price, position in the waterfall, senior versus subordinated position and attachment points. (b) Rep resents discount rates, estimates and assumptions that we believe would be used by market participants when valuing these assets and liabilities. (c) Mortality inputs are shown as multipliers of the 2012 Individual Annuity Mortality Basic table. The ranges of reported inputs for Obligations of states, municipalities and political subdivisions, Corporate debt, RMBS, CDO/ABS, and CMBS valued using a discounted cash flow technique consist of one standard deviation in either direction from the value -weighted av erage. The preceding table does not give effect to our risk management practices that might offset risks inherent in these Level 3 assets and liabilities. Sensitivity to Changes in Unobservable Inputs We consider unobservable inputs to be those for which m arket data is not available and that are developed using the best information available to us about the assumptions that market participants would use when pricing the asset or liability. Relevant inputs vary depending on the nature of the instrument being measured at fair value. The following paragraphs provide a general description of sensitivities of significant unobservable inputs along with interrelationships between and among the significant unobservable inputs and their impact on the fair value measu rements. The effect of a change in a particular assumption in the sensitivity analysis below is considered independently of changes in any other assumptions. In practice, simultaneous changes in assumptions may not always have a linear effect on the inputs discussed below. Interrelationships may also exist between observable and unobservable inputs. Such relationships have not been included in the discussion below. For each of the individual relationships described below, the inverse relationship would also gen erally apply. Obligations of States, Municipalities and Political Subdivisions The significant unobservable input used in the fair value measurement of certain investments in obligations of states, municipalities and political subdivisions is yield. I n general, increases in the yield would decrease the fair value of investments in obligations of states, municipalities and political subdivisions. Corporate Debt Corporate debt securities included in Level 3 are primarily private placement issuances that are not traded in active markets or that are subject to transfer restrictions. Fair value measurements consider illiquidity and non- transferability. When observable price quotations are not available, fair value is determined based on discounted cash flow models using discount rates based on credit spreads, yields or price levels of publicly -traded debt of the issuer or other comparable securities, considering illiquidity and structure. The significant unobservable input used in the fair value measurement o f corporate debt is the yield. The yield is affected by the market movements in credit spreads and U.S. Treasury yields. In addition, the migration in credit quality of a given security generally has a corresponding effect on the fair value measurement of the security. For example, a downward migration of credit quality would increase spreads. Holding U.S. Treasury rates constant, an increase in corporate credit spreads would decrease the fair value of corporate debt . RMBS and CDO/ABS The significant unob servable inputs used in fair value measurements of RMBS and certain CDO/ABS valued by third -party valuation service providers are constant prepayment rates (CPR), loss severity, constant default rates (CDR) and yield. A change in the assumptions used for t he probability of default will generally be accompanied by a corresponding change in the assumption used for the loss severity and an inverse change in the assumption used for prepayment rates. In general, increases in CPR, loss severity, CDR and yield, in isolation, would result in a decrease in the fair value measurement. Changes in fair value based on variations in assumptions generally cannot be extrapolated because the relationship between the directional change of each input is not usually linear . CMB S The significant unobservable input used in fair value measurements for CMBS is the yield. Prepayment assumptions for each mortgage pool are factored into the yield. CMBS generally feature a lower degree of prepayment risk than RMBS because commercial mor tgages generally contain a penalty for prepayment. In general, increases in the yield would decrease the fair value of CMBS . Embedded derivatives within Policyholder contract deposits Embedded derivatives reported within Policyholder co ntract deposits include GMWB within variable annuity products and interest crediting rates based on market indices within index annuities, indexed life and GICs . For any given contract, assumptions for unobservable inputs vary throughout the period over which cash flows are projected for purposes of valuing the emb edded derivative. The following unobservable inputs are used for valuing embedded derivatives measured at fair value: Long-term equity volatilities represent equity volatility beyond the period for which observable equity volatilities are available. Increa ses in assumed volatility will generally increase the fair value of both the projected cash flows from rider fees as well as the projected cash flows related to benefit payments . Therefore, the net change in the fair value of the liability may be either a decrease or an increase, depending on the relative changes in projected rider fees and projected benefit payments. Equity / interest rate correlation estimates the relationship between changes in equity returns and interest rates in the economic scenario generator used to value our GMWB embedded derivatives. In general, a higher positive correlation assumes that equity markets and interest rates move in a more correlated fashion, which generally increases the fair value of the liability. Base lapse rate assumptions are determined by company experience and are adjusted at the contract level using a dynamic lapse function, which reduces the base lapse rate when the contract is in-the-money (when the contract holder’s guaranteed value, as estimated by the c ompany, is worth more than their underlying account value). Lapse rates are also generally assumed to be lower in periods when a surrender charge applies. Increases in assumed lapse rates will generally decrease the fair value of the liability, as fewer po licyholders would persist to collect guaranteed withdrawal amounts. Mortality rate assumptions, which vary by age and gender, are based on company experience and include a mortality improvement assumption. Increases in assumed mortality rates will decreas e the fair value of the liability, while lower mortality rate assumptions will generally increase the fair value of the liability, because guaranteed payments will be made for a longer period of time. Utilization assumptions estimate the timing when policy holders with a GMWB will elect to utilize their benefit and begin taking withdrawals. The assumptions may vary by the type of guarantee, tax-qualified status, the contract’s withdrawal history and the age of the policyholder. Utilization assumptions are b ased on company experience, which includes partial withdrawal behavior. Increases in assumed utilization rates will generally increase the fair value of the liability. Option budget estimates the expected long-term cost of options used to hedge exposures a ssociated with equity price changes. The level of option budgets determines future costs of the options, which impacts the growth in account value and the valuation of embedded derivatives. Investments in C ertain E ntities C arried at F air V alue U sing N et A sset Value P er S hare The following table includes information related to our investments in certain other invested assets, including private equity funds, hedge funds and other alternative investments that calculate net asset value per share (or its equivalent). For these investments, which are measured at fair value on a recurring basis, we use the net asset value per share to measure fair value. March 31, 2019 December 31, 2018 Fair Value Fair Value Using NAV Using NAV Per Share (or Unfunded Per Share (or Unfunded (in millions) Investment Category Includes its equivalent) Commitments its equivalent) Commitments Investment Category Private equity funds: Leveraged buyout Debt and/or equity investments made as part of a transaction in which assets of mature companies are acquired from the current shareholders, typically with the use of financial leverage $ 970 $ 1,378 $ 847 $ 1,327 Real Estate / Infrastructure Investments in real estate properties and infrastructure positions, including power plants and other energy generating facilities 232 179 190 83 Venture capital Early-stage, high-potential, growth companies expected to generate a return through an eventual realization event, such as an initial public offering or sale of the company 130 116 126 127 Growth Equity Funds that make investments in established companies for the purpose of growing their businesses 371 29 362 28 Mezzanine Funds that make investments in the junior debt and equity securities of leveraged companies 218 97 211 75 Other Includes distressed funds that invest in securities of companies that are in default or under bankruptcy protection, as well as funds that have multi-strategy, and other strategies 623 285 514 307 Total private equity funds 2,544 2,084 2,250 1,947 Hedge funds: Event-driven Securities of companies undergoing material structural changes, including mergers, acquisitions and other reorganizations 815 - 787 - Long-short Securities that the manager believes are undervalued, with corresponding short positions to hedge market risk 725 - 863 - Macro Investments that take long and short positions in financial instruments based on a top-down view of certain economic and capital market conditions 820 - 887 - Distressed Securities of companies that are in default, under bankruptcy protection or troubled 18 - 21 8 Other Includes investments held in funds that are less liquid, as well as other strategies which allow for broader allocation between public and private investments 160 1 158 1 Total hedge funds 2,538 1 2,716 9 Total $ 5,082 $ 2,085 $ 4,966 $ 1,956 Private equity fund investments included above are not redeemable, because distributions from the funds will be received when underlying investments of the funds are liquidated. Private equity funds a |