Mortgage-Backed Securities and other securities | 10 years and < or equal to 20 years > 20 years and < or equal to 30 years > 30 years Total Agency CMBS $ 973,189 $ 462,288 $ — $ — $ 1,435,477 Agency CMBS Interest-Only Strips, accounted for as derivatives — — — 3,092 — 3,092 Agency RMBS — — 340,771 — 340,771 Agency RMBS Interest-Only Strips 2,413 1,966 5,964 — 10,343 Agency RMBS Interest-Only Strips, accounted for as derivatives 669 3,893 1,010 — 5,572 Subtotal Agency 976,271 468,147 347,745 3,092 1,795,255 Non-Agency RMBS — — 8,966 29,165 38,131 Non-Agency RMBS Interest-Only Strips — — 1,716 5,967 7,683 Non-Agency CMBS 89,782 125,282 92,610 8,345 316,019 Subtotal Non-Agency 89,782 125,282 103,292 43,477 361,833 Other securities 25,824 31,823 2,768 19,746 80,161 Total $ 1,091,877 $ 625,252 $ 453,805 $ 66,315 $ 2,237,249 December 31, 2018 < or equal to 10 years > 10 years and < or equal to 20 years > 20 years and < or equal to 30 years > 30 years Total Agency CMBS $ 1,101,820 $ 380,164 $ — $ — $ 1,481,984 Agency CMBS Interest-Only Strips, accounted for as derivatives — — — 4,158 4,158 Agency RMBS Interest-Only Strips 3,577 2,402 6,156 — 12,135 Agency RMBS Interest-Only Strips, accounted for as derivatives 1,089 4,053 2,560 — 7,702 Subtotal Agency 1,106,486 386,619 8,716 4,158 1,505,979 Non-Agency RMBS — — 8,540 30,486 39,026 Non-Agency RMBS Interest-Only Strips — — 4,310 7,219 11,529 Non-Agency CMBS 28,754 53,653 72,921 44,973 200,301 Subtotal Non-Agency 28,754 53,653 85,771 82,678 250,856 Other securities 7,698 26,020 — 26,188 59,906 Total $ 1,142,938 $ 466,292 $ 94,487 $ 113,024 $ 1,816,741 The following tables present the gross unrealized losses and estimated fair value of the Company's MBS and other securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2019 and December 31, 2018 (dollars in thousands): December 31, 2019 Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Agency CMBS $ 214,084 $ (5,798 ) 16 $ — $ — — $ 214,084 $ (5,798 ) 16 Agency RMBS Interest-Only Strips 1,376 (43 ) 4 1,828 (95 ) 7 3,204 (138 ) 11 Subtotal Agency 215,460 (5,841 ) 20 1,828 (95 ) 7 217,288 (5,936 ) 27 Non-Agency RMBS 13,214 (260 ) 1 — — — 13,214 (260 ) 1 Non-Agency RMBS Interest-Only Strips 1,716 (658 ) 1 — — — 1,716 (658 ) 1 Non-Agency CMBS 171,650 (4,302 ) 31 18,069 (571 ) 4 189,719 (4,873 ) 35 Subtotal Non-Agency 186,580 (5,220 ) 33 18,069 (571 ) 4 204,649 (5,791 ) 37 Other securities 10,512 (206 ) 2 — — — 10,512 (206 ) 2 Total $ 412,552 $ (11,267 ) 55 $ 19,897 $ (666 ) 11 $ 432,449 $ (11,933 ) 66 December 31, 2018 Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Agency CMBS $ 29,413 $ (307 ) 3 $ 879,549 $ (29,287 ) 72 $ 908,962 $ (29,594 ) 75 Agency RMBS Interest-Only Strips 3,277 (124 ) 7 3,917 (283 ) 9 7,194 (407 ) 16 Subtotal Agency 32,690 (431 ) 10 883,466 (29,570 ) 81 916,156 (30,001 ) 91 Non-Agency RMBS — — — 500 — 1 500 — 1 Non-Agency RMBS Interest-Only Strips 957 (7 ) 2 — — — 957 (7 ) 2 Non-Agency CMBS 65,339 (712 ) 7 19,323 (1,933 ) 3 84,662 (2,645 ) 10 Subtotal Non-Agency 66,296 (719 ) 9 19,823 (1,933 ) 4 86,119 (2,652 ) 13 Other securities 15,208 (390 ) 2 — — — 15,208 (390 ) 2 Total $ 114,194 $ (1,540 ) 21 $ 903,289 $ (31,503 ) 85 $ 1,017,483 $ (33,043 ) 106 At December 31, 2019 and December 31, 2018 , the Company did not intend to sell any of its MBS and other securities that were in an unrealized loss position, and it is “more likely than not” that the Company will not be required to sell these MBS and other securities before recovery of their amortized cost basis, which may be at their maturity date. Generally, the Company records Other Than Temporary Impairment ("OTTI") when the credit quality of the underlying collateral deteriorates, and or the scheduled payments are faster than previously projected. The credit deterioration could be as a result of, but not limited to, increased projected realized losses, foreclosures, delinquencies and the likelihood of the borrower being able to make payments in the future. Generally, a prepayment occurs when a loan has a higher interest rate relative to current interest rates and lenders are willing to extend credit at the lower current interest rate or the underlying collateral for the loan is sold or transferred. Refer to Note 2 "Summary of Significant Accounting Policies - Mortgage-Backed Securities and Other Securities." The following table presents the OTTI the Company recorded on its securities portfolio (dollars in thousands): For the year ended December 31, 2019 For the year ended December 31, 2018 For the year ended December 31, 2017 Agency RMBS (1) $ 74 $ 807 $ 5,774 Non-Agency RMBS 1,331 996 — Non-Agency CMBS 6,565 8,660 15,117 Other securities 604 717 1,982 Total $ 8,574 $ 11,180 $ 22,873 (1) Other-than-temporary impairment on Agency RMBS includes impairments on Agency RMBS IOs and unrealized loss on Agency RMBS securities that the Company had the intent to sell at the end of the period, if applicable. The following table presents components of interest income on the Company's MBS and other securities for the three years ended December 31, 2019 , December 31, 2018 and December 31, 2017 , respectively (dollars in thousands): For the year ended December 31, 2019 For the year ended December 31, 2018 For the year ended December 31, 2017 Coupon Interest Net (Premium Amortization/ Amortization Basis) Discount Amortization Interest Income Coupon Interest Net (Premium Amortization/ Amortization Basis) Discount Amortization Interest Income Coupon Interest Net (Premium Amortization/ Amortization Basis) Discount Amortization Interest Income Agency CMBS $ 51,286 $ (2,327 ) $ 48,959 $ 60,148 $ (646 ) $ 59,502 $ 40,064 $ 507 $ 40,571 Agency RMBS 12,181 (3,053 ) 9,128 19,507 (5,092 ) 14,415 38,108 (13,058 ) 25,050 Non-Agency RMBS 4,682 (2,214 ) 2,468 7,120 (1,073 ) 6,047 5,602 525 6,127 Non-Agency CMBS 14,178 4,017 18,195 20,058 6,366 26,424 19,179 8,276 27,455 Other securities 11,633 (6,472 ) 5,161 14,805 (6,371 ) 8,434 8,280 1,559 9,839 Total $ 93,960 $ (10,049 ) $ 83,911 $ 121,638 $ (6,816 ) $ 114,822 $ 111,233 $ (2,191 ) $ 109,042 The following tables present the sales and realized gains (losses) of the Company's MBS and other securities for the three years ended December 31, 2019 , December 31, 2018 and December 31, 2017 , respectively (dollars in thousands): For the year ended December 31, 2019 Proceeds Gross Gains Gross Losses Net Gain (Loss) Agency CMBS $ 891,072 $ 32,793 $ (4,190 ) $ 28,603 Agency RMBS 205,310 1,559 — 1,559 Non-Agency CMBS 40,235 317 (1,624 ) (1,307 ) Total $ 1,136,617 $ 34,669 $ (5,814 ) $ 28,855 For the year ended December 31, 2018 Proceeds Gross Gains Gross Losses Net Gain (Loss) Agency CMBS $ 1,534,967 $ — $ (51,045 ) $ (51,045 ) Agency RMBS 589,854 18 (23,997 ) (23,979 ) Non-Agency RMBS 99,842 7,008 (478 ) 6,530 Non-Agency CMBS 140,292 3,086 (6,201 ) (3,115 ) Other securities 65,099 8,400 — 8,400 Total $ 2,430,054 $ 18,512 $ (81,721 ) $ (63,209 ) For the year ended December 31, 2017 Proceeds Gross Gains Gross Losses Net Gain (Loss) Agency RMBS (1) $ 1,251,985 $ 5,020 $ (7,936 ) $ (2,916 ) Non-Agency RMBS (2) 243,838 24,356 (2,241 ) 22,115 Non-Agency CMBS 54,875 2,543 (1,803 ) 740 Other securities 38,447 713 (54 ) 659 Total $ 1,589,145 $ 32,632 $ (12,034 ) $ 20,598 (1) Excludes proceeds for Agency RMBS Interest-Only Strips, accounted for as derivatives, of approximately $2.6 million and gross realized gains of approximately $432 thousand . (2) Excludes proceeds for Non-Agency RMBS Interest-Only Strips, accounted for as derivatives, of approximately $2.2 million , gross realized gains of $274 thousand and gross realized losses of $180 thousand . Unconsolidated CMBS VIEs The Company’s economic interests held in unconsolidated CMBS VIEs are limited in nature to those of a passive holder of CMBS issued by securitization trusts; the Company was not involved in the design or creation of the securitization trusts. The Company evaluates its CMBS holdings for potential consolidation of the securitized trust, in which it owns the most subordinate tranche or a portion of the controlling class. As of December 31, 2019 and December 31, 2018 , the Company held ten and seven variable interests in unconsolidated CMBS VIEs, respectively, in which it either owned the most subordinate class or a portion of the controlling class. The Company determined it was not the primary beneficiary and accordingly, the CMBS VIEs were not consolidated in the Company’s consolidated financial statements. As of December 31, 2019 and December 31, 2018 , the Company’s maximum exposure to loss from these variable interests did not exceed the carrying value of these investments of $117.7 million and $118.4 million , respectively. These investments are classified in "Non-Agency mortgage-backed securities, at fair value" in the Company’s Consolidated Balance Sheets. Further, as of December 31, 2019 and December 31, 2018 , the Company did not guarantee any obligations of unconsolidated entities or enter into any commitment or intent to provide funding to any such entities." id="sjs-B4">Mortgage-Backed Securities and other securities The following tables present certain information about the Company's investment portfolio at December 31, 2019 and December 31, 2018 (dollars in thousands): December 31, 2019 Principal Balance Unamortized Premium (Discount), net Discount Designated as Credit Reserve and OTTI Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Net Weighted Average Coupon Agency CMBS $ 1,347,929 $ 26,514 $ — $ 1,374,443 $ 66,832 $ (5,798 ) $ 1,435,477 3.4 % Agency CMBS Interest-Only Strips, accounted for as derivatives (1)(2) N/A N/A N/A N/A N/A N/A 3,092 0.4 % Subtotal Agency CMBS 1,347,929 26,514 — 1,374,443 66,832 (5,798 ) 1,438,569 3.1 % Agency RMBS 327,814 5,473 — 333,287 7,484 — 340,771 3.5 % Agency RMBS Interest-Only Strips (1) N/A N/A N/A 8,661 1,820 (138 ) 10,343 2.8 % Agency RMBS Interest-Only Strips, accounted for as derivatives (1)(2) N/A N/A N/A N/A N/A N/A 5,572 3.0 % Subtotal Agency RMBS 327,814 5,473 — 341,948 9,304 (138 ) 356,686 3.3 % Total Agency MBS 1,675,743 31,987 — 1,716,391 76,136 (5,936 ) 1,795,255 3.1 % Non-Agency RMBS 52,767 4,492 (20,256 ) 37,003 1,388 (260 ) 38,131 4.8 % Non-Agency RMBS Interest- Only Strips (1) N/A N/A N/A 7,705 636 (658 ) 7,683 0.6 % Subtotal Non-Agency RMBS 52,767 4,492 (20,256 ) 44,708 2,024 (918 ) 45,814 1.0 % Non-Agency CMBS 354,458 (17,909 ) (22,016 ) 314,533 6,359 (4,873 ) 316,019 5.1 % Total Non-Agency MBS 407,225 (13,417 ) (42,272 ) 359,241 8,383 (5,791 ) 361,833 2.7 % Other securities (3) 71,896 (2,437 ) (6,203 ) 73,975 6,392 (206 ) 80,161 6.7 % Total $ 2,154,864 $ 16,133 $ (48,475 ) $ 2,149,607 $ 90,911 $ (11,933 ) $ 2,237,249 3.1 % December 31, 2018 Principal Balance Unamortized Premium (Discount), net Discount Designated as Credit Reserve and OTTI Amortized Cost Unrealized Gain Unrealized Loss Estimated Fair Value Net Weighted Average Coupon Agency CMBS $ 1,493,675 $ 5,820 $ — $ 1,499,495 $ 12,083 $ (29,594 ) $ 1,481,984 3.3 % Agency CMBS Interest-Only Strips, accounted for as derivatives (1)(2) N/A N/A N/A N/A N/A N/A 4,158 0.4 % Subtotal Agency CMBS 1,493,675 5,820 — 1,499,495 12,083 (29,594 ) 1,486,142 3.0 % Agency RMBS Interest-Only Strips (1) N/A N/A N/A 11,480 1,062 (407 ) 12,135 2.2 % Agency RMBS Interest-Only Strips, accounted for as derivatives (1)(2) N/A N/A N/A N/A N/A N/A 7,702 2.9 % Subtotal Agency RMBS — — — 11,480 1,062 (407 ) 19,837 2.5 % Total Agency MBS 1,493,675 5,820 — 1,510,975 13,145 (30,001 ) 1,505,979 2.9 % Non-Agency RMBS 54,887 6,909 (23,731 ) 38,065 961 — 39,026 4.8 % Non-Agency RMBS Interest- Only Strips (1) N/A N/A N/A 11,154 382 (7 ) 11,529 0.6 % Subtotal Non-Agency RMBS 54,887 6,909 (23,731 ) 49,219 1,343 (7 ) 50,555 1.0 % Non-Agency CMBS 240,431 (20,317 ) (22,189 ) 197,925 5,021 (2,645 ) 200,301 5.9 % Total Non-Agency MBS 295,318 (13,408 ) (45,920 ) 247,144 6,364 (2,652 ) 250,856 2.4 % Other securities (3) 47,042 (1,129 ) (7,603 ) 55,284 5,012 (390 ) 59,906 9.0 % Total $ 1,836,035 $ (8,717 ) $ (53,523 ) $ 1,813,403 $ 24,521 $ (33,043 ) $ 1,816,741 2.9 % (1) IOs and IIOs have no principal balances and bear interest based on a notional balance. The notional balance is used solely to determine interest distributions on interest-only class of securities. At December 31, 2019 , the notional balance for Agency RMBS IOs and IIOs, Non-Agency RMBS IOs and IIOs, Agency RMBS IOs and IIOs, accounted for as derivatives, and Agency CMBS IOs and IIOs, accounted for as derivatives was $121.7 million , $442.4 million , $64.8 million and $160.2 million , respectively. At December 31, 2018 , the notional balance for Agency RMBS IOs and IIOs, Non-Agency RMBS IOs and IIOs, Agency RMBS IOs and IIOs, accounted for as derivatives and Agency CMBS IOs and IIOs, accounted for as derivatives was $158.8 million , $519.9 million , $89.8 million , $172.2 million , respectively. (2) Interest on these securities is reported as a component of "Gain (loss) on derivative instruments, net" in the Consolidated Statements of Operations. (3) Other securities include residual interests in asset-backed securities which have no principal balance and an amortized cost of approximately $10.7 million and $17.0 million , as of December 31, 2019 and December 31, 2018 , respectively. As of December 31, 2019 and December 31, 2018 , the weighted average expected remaining term of the MBS and other securities investment portfolio was 7.9 years and 8.5 years , respectively. The following table presents the changes in the components of the Company's purchase discount and amortizable premium on its Non-Agency RMBS, Non-Agency CMBS and other securities for the years ended December 31, 2019 , December 31, 2018 and December 31, 2017 (dollars in thousands): Year ended December 31, 2019 Year ended December 31, 2018 Year ended December 31, 2017 Discount Designated as Credit Reserve and OTTI Accretable Discount (1) Amortizable Premium (1) Discount Designated as Accretable Discount (1) Amortizable Premium (1) Discount Designated as Credit Reserve and OTTI Accretable Discount (1) Amortizable Premium (1) Balance at beginning of period $ (53,523 ) $ (29,465 ) $ 14,928 $ (72,915 ) $ (68,438 ) $ 20,872 $ (130,484 ) $ (109,822 ) $ 44,527 Accretion of discount — 4,364 — — 7,137 — — 10,715 — Amortization of premium — — (1,215 ) — — (675 ) — — (843 ) Realized credit losses 7,290 — — 5,863 — — 2,391 — — Purchases (28 ) (7,953 ) 819 (7,182 ) (6,473 ) 435 (19,385 ) (1,205 ) 7,259 Sales 26,706 — (19,640 ) 32,301 40,338 (9,590 ) 89,628 33,166 (31,118 ) Net impairment losses recognized in earnings (6,612 ) — — (9,733 ) — — (15,310 ) — — Transfers/release of credit reserve (2) (22,308 ) 2,889 19,419 (1,857 ) (2,029 ) 3,886 245 (1,292 ) 1,047 Balance at end of period $ (48,475 ) $ (30,165 ) $ 14,311 $ (53,523 ) $ (29,465 ) $ 14,928 $ (72,915 ) $ (68,438 ) $ 20,872 (1) Together with coupon interest, accretable purchase discount and amortizable premium is recognized as interest income over the life of the security. (2) Subsequent reductions of a security's non-accretable discount results in a corresponding reduction in its amortizable premium. The following tables present the fair value and contractual maturities of the Company's investment securities at December 31, 2019 and December 31, 2018 (dollars in thousands): December 31, 2019 < or equal to 10 years > 10 years and < or equal to 20 years > 20 years and < or equal to 30 years > 30 years Total Agency CMBS $ 973,189 $ 462,288 $ — $ — $ 1,435,477 Agency CMBS Interest-Only Strips, accounted for as derivatives — — — 3,092 — 3,092 Agency RMBS — — 340,771 — 340,771 Agency RMBS Interest-Only Strips 2,413 1,966 5,964 — 10,343 Agency RMBS Interest-Only Strips, accounted for as derivatives 669 3,893 1,010 — 5,572 Subtotal Agency 976,271 468,147 347,745 3,092 1,795,255 Non-Agency RMBS — — 8,966 29,165 38,131 Non-Agency RMBS Interest-Only Strips — — 1,716 5,967 7,683 Non-Agency CMBS 89,782 125,282 92,610 8,345 316,019 Subtotal Non-Agency 89,782 125,282 103,292 43,477 361,833 Other securities 25,824 31,823 2,768 19,746 80,161 Total $ 1,091,877 $ 625,252 $ 453,805 $ 66,315 $ 2,237,249 December 31, 2018 < or equal to 10 years > 10 years and < or equal to 20 years > 20 years and < or equal to 30 years > 30 years Total Agency CMBS $ 1,101,820 $ 380,164 $ — $ — $ 1,481,984 Agency CMBS Interest-Only Strips, accounted for as derivatives — — — 4,158 4,158 Agency RMBS Interest-Only Strips 3,577 2,402 6,156 — 12,135 Agency RMBS Interest-Only Strips, accounted for as derivatives 1,089 4,053 2,560 — 7,702 Subtotal Agency 1,106,486 386,619 8,716 4,158 1,505,979 Non-Agency RMBS — — 8,540 30,486 39,026 Non-Agency RMBS Interest-Only Strips — — 4,310 7,219 11,529 Non-Agency CMBS 28,754 53,653 72,921 44,973 200,301 Subtotal Non-Agency 28,754 53,653 85,771 82,678 250,856 Other securities 7,698 26,020 — 26,188 59,906 Total $ 1,142,938 $ 466,292 $ 94,487 $ 113,024 $ 1,816,741 The following tables present the gross unrealized losses and estimated fair value of the Company's MBS and other securities by length of time that such securities have been in a continuous unrealized loss position at December 31, 2019 and December 31, 2018 (dollars in thousands): December 31, 2019 Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Agency CMBS $ 214,084 $ (5,798 ) 16 $ — $ — — $ 214,084 $ (5,798 ) 16 Agency RMBS Interest-Only Strips 1,376 (43 ) 4 1,828 (95 ) 7 3,204 (138 ) 11 Subtotal Agency 215,460 (5,841 ) 20 1,828 (95 ) 7 217,288 (5,936 ) 27 Non-Agency RMBS 13,214 (260 ) 1 — — — 13,214 (260 ) 1 Non-Agency RMBS Interest-Only Strips 1,716 (658 ) 1 — — — 1,716 (658 ) 1 Non-Agency CMBS 171,650 (4,302 ) 31 18,069 (571 ) 4 189,719 (4,873 ) 35 Subtotal Non-Agency 186,580 (5,220 ) 33 18,069 (571 ) 4 204,649 (5,791 ) 37 Other securities 10,512 (206 ) 2 — — — 10,512 (206 ) 2 Total $ 412,552 $ (11,267 ) 55 $ 19,897 $ (666 ) 11 $ 432,449 $ (11,933 ) 66 December 31, 2018 Less than 12 Months 12 Months or More Total Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Fair Value Unrealized Losses Number of Securities Agency CMBS $ 29,413 $ (307 ) 3 $ 879,549 $ (29,287 ) 72 $ 908,962 $ (29,594 ) 75 Agency RMBS Interest-Only Strips 3,277 (124 ) 7 3,917 (283 ) 9 7,194 (407 ) 16 Subtotal Agency 32,690 (431 ) 10 883,466 (29,570 ) 81 916,156 (30,001 ) 91 Non-Agency RMBS — — — 500 — 1 500 — 1 Non-Agency RMBS Interest-Only Strips 957 (7 ) 2 — — — 957 (7 ) 2 Non-Agency CMBS 65,339 (712 ) 7 19,323 (1,933 ) 3 84,662 (2,645 ) 10 Subtotal Non-Agency 66,296 (719 ) 9 19,823 (1,933 ) 4 86,119 (2,652 ) 13 Other securities 15,208 (390 ) 2 — — — 15,208 (390 ) 2 Total $ 114,194 $ (1,540 ) 21 $ 903,289 $ (31,503 ) 85 $ 1,017,483 $ (33,043 ) 106 At December 31, 2019 and December 31, 2018 , the Company did not intend to sell any of its MBS and other securities that were in an unrealized loss position, and it is “more likely than not” that the Company will not be required to sell these MBS and other securities before recovery of their amortized cost basis, which may be at their maturity date. Generally, the Company records Other Than Temporary Impairment ("OTTI") when the credit quality of the underlying collateral deteriorates, and or the scheduled payments are faster than previously projected. The credit deterioration could be as a result of, but not limited to, increased projected realized losses, foreclosures, delinquencies and the likelihood of the borrower being able to make payments in the future. Generally, a prepayment occurs when a loan has a higher interest rate relative to current interest rates and lenders are willing to extend credit at the lower current interest rate or the underlying collateral for the loan is sold or transferred. Refer to Note 2 "Summary of Significant Accounting Policies - Mortgage-Backed Securities and Other Securities." The following table presents the OTTI the Company recorded on its securities portfolio (dollars in thousands): For the year ended December 31, 2019 For the year ended December 31, 2018 For the year ended December 31, 2017 Agency RMBS (1) $ 74 $ 807 $ 5,774 Non-Agency RMBS 1,331 996 — Non-Agency CMBS 6,565 8,660 15,117 Other securities 604 717 1,982 Total $ 8,574 $ 11,180 $ 22,873 (1) Other-than-temporary impairment on Agency RMBS includes impairments on Agency RMBS IOs and unrealized loss on Agency RMBS securities that the Company had the intent to sell at the end of the period, if applicable. The following table presents components of interest income on the Company's MBS and other securities for the three years ended December 31, 2019 , December 31, 2018 and December 31, 2017 , respectively (dollars in thousands): For the year ended December 31, 2019 For the year ended December 31, 2018 For the year ended December 31, 2017 Coupon Interest Net (Premium Amortization/ Amortization Basis) Discount Amortization Interest Income Coupon Interest Net (Premium Amortization/ Amortization Basis) Discount Amortization Interest Income Coupon Interest Net (Premium Amortization/ Amortization Basis) Discount Amortization Interest Income Agency CMBS $ 51,286 $ (2,327 ) $ 48,959 $ 60,148 $ (646 ) $ 59,502 $ 40,064 $ 507 $ 40,571 Agency RMBS 12,181 (3,053 ) 9,128 19,507 (5,092 ) 14,415 38,108 (13,058 ) 25,050 Non-Agency RMBS 4,682 (2,214 ) 2,468 7,120 (1,073 ) 6,047 5,602 525 6,127 Non-Agency CMBS 14,178 4,017 18,195 20,058 6,366 26,424 19,179 8,276 27,455 Other securities 11,633 (6,472 ) 5,161 14,805 (6,371 ) 8,434 8,280 1,559 9,839 Total $ 93,960 $ (10,049 ) $ 83,911 $ 121,638 $ (6,816 ) $ 114,822 $ 111,233 $ (2,191 ) $ 109,042 The following tables present the sales and realized gains (losses) of the Company's MBS and other securities for the three years ended December 31, 2019 , December 31, 2018 and December 31, 2017 , respectively (dollars in thousands): For the year ended December 31, 2019 Proceeds Gross Gains Gross Losses Net Gain (Loss) Agency CMBS $ 891,072 $ 32,793 $ (4,190 ) $ 28,603 Agency RMBS 205,310 1,559 — 1,559 Non-Agency CMBS 40,235 317 (1,624 ) (1,307 ) Total $ 1,136,617 $ 34,669 $ (5,814 ) $ 28,855 For the year ended December 31, 2018 Proceeds Gross Gains Gross Losses Net Gain (Loss) Agency CMBS $ 1,534,967 $ — $ (51,045 ) $ (51,045 ) Agency RMBS 589,854 18 (23,997 ) (23,979 ) Non-Agency RMBS 99,842 7,008 (478 ) 6,530 Non-Agency CMBS 140,292 3,086 (6,201 ) (3,115 ) Other securities 65,099 8,400 — 8,400 Total $ 2,430,054 $ 18,512 $ (81,721 ) $ (63,209 ) For the year ended December 31, 2017 Proceeds Gross Gains Gross Losses Net Gain (Loss) Agency RMBS (1) $ 1,251,985 $ 5,020 $ (7,936 ) $ (2,916 ) Non-Agency RMBS (2) 243,838 24,356 (2,241 ) 22,115 Non-Agency CMBS 54,875 2,543 (1,803 ) 740 Other securities 38,447 713 (54 ) 659 Total $ 1,589,145 $ 32,632 $ (12,034 ) $ 20,598 (1) Excludes proceeds for Agency RMBS Interest-Only Strips, accounted for as derivatives, of approximately $2.6 million and gross realized gains of approximately $432 thousand . (2) Excludes proceeds for Non-Agency RMBS Interest-Only Strips, accounted for as derivatives, of approximately $2.2 million , gross realized gains of $274 thousand and gross realized losses of $180 thousand . Unconsolidated CMBS VIEs The Company’s economic interests held in unconsolidated CMBS VIEs are limited in nature to those of a passive holder of CMBS issued by securitization trusts; the Company was not involved in the design or creation of the securitization trusts. The Company evaluates its CMBS holdings for potential consolidation of the securitized trust, in which it owns the most subordinate tranche or a portion of the controlling class. As of December 31, 2019 and December 31, 2018 , the Company held ten and seven variable interests in unconsolidated CMBS VIEs, respectively, in which it either owned the most subordinate class or a portion of the controlling class. The Company determined it was not the primary beneficiary and accordingly, the CMBS VIEs were not consolidated in the Company’s consolidated financial statements. As of December 31, 2019 and December 31, 2018 , the Company’s maximum exposure to loss from these variable interests did not exceed the carrying value of these investments of $117.7 million and $118.4 million , respectively. These investments are classified in "Non-Agency mortgage-backed securities, at fair value" in the Company’s Consolidated Balance Sheets. Further, as of December 31, 2019 and December 31, 2018 , the Company did not guarantee any obligations of unconsolidated entities or enter into any commitment or intent to provide funding to any such entities. |