Investment Securities Available for Sale (Tables)

6 Months Ended

Jun. 30, 2018

Summary of Available-for-Sale Investment Securities

The amortized cost, gross unrealized gains and losses, and estimated fair values of investment securities available for sale at June 30, 2018 and December 31, 2017 are summarized below.



	June 30, 2018
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	122,800	$	—	$	(2,167	)	$	120,633
U.S. Government agency securities	40,753		181		—			40,934
Mortgage-backed securities issued by U.S. Government agencies	111,406		107		(3,569		)	107,944
Mortgage-backed securities issued by U.S. Government sponsored enterprises	2,614,668		59		(87,882		)	2,526,845
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	1,159,859		139		(43,550		)	1,116,448
State and municipal securities	115		—		—			115
Corporate debt and other debt securities	17,000		186		(143		)	17,043
Total investment securities available for sale	$	4,066,601	$	672	$	(137,311	)	$	3,929,962

	December 31, 2017
(in thousands)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses			Fair Value
U.S. Treasury securities	$	83,608	$	—	$	(934	)	$	82,674
U.S. Government agency securities	10,771		91		—			10,862
Mortgage-backed securities issued by U.S. Government agencies	121,283		519		(1,362		)	120,440
Mortgage-backed securities issued by U.S. Government sponsored enterprises	2,666,818		5,059		(31,354		)	2,640,523
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	1,135,259		144		(23,404		)	1,111,999
State and municipal securities	180		—		—			180
Corporate debt and other securities	20,320		294		(223		)	20,391
Total investment securities available for sale	$	4,038,239	$	6,107	$	(57,277	)	$	3,987,069

Schedule of Unrealized Loss on Investments

Gross unrealized losses on investment securities and the fair value of the related securities, aggregated by investment category and length of time that individual securities have been in a continuous unrealized loss position, at June 30, 2018 and December 31, 2017 are presented below.



	June 30, 2018
	Less than 12 Months				12 Months or Longer				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Treasury securities	$	72,386	$	1,378	$	29,255	$	789	$	101,641	$	2,167
Mortgage-backed securities issued by U.S. Government agencies	23,240		632		67,765		2,937		91,005		3,569
Mortgage-backed securities issued by U.S. Government sponsored enterprises	1,703,526		49,197		812,767		38,685		2,516,293		87,882
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	609,505		21,190		412,961		22,360		1,022,466		43,550
Corporate debt and other debt securities	—		—		1,857		143		1,857		143
Total	$	2,408,657	$	72,397	$	1,324,605	$	64,914	$	3,733,262	$	137,311

	December 31, 2017
	Less than 12 Months				12 Months or Longer				Total
(in thousands)	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses
U.S. Treasury securities	$	34,243	$	443	$	29,562	$	491	$	63,805	$	934
Mortgage-backed securities issued by U.S. Government agencies	36,810		357		55,740		1,005		92,550		1,362
Mortgage-backed securities issued by U.S. Government sponsored enterprises	1,271,012		10,263		929,223		21,091		2,200,235		31,354
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	653,781		9,497		426,237		13,907		1,080,018		23,404
Corporate debt and other securities	—		—		5,097		223		5,097		223
Total	$	1,995,846	$	20,560	$	1,445,859	$	36,717	$	3,441,705	$	57,277

Amortized Cost and Estimated Fair Value by Contractual Maturity of Investment Securities Available-for-Sale

For purposes of the maturity table, mortgage-backed securities and CMOs, which are not due at a single maturity date, have been classified based on the final contractual maturity date.



	Distribution of Maturities at June 30, 2018
(in thousands)	Within One Year		1 to 5 Years		5 to 10 Years		More Than 10 Years		Total
Amortized Cost
U.S. Treasury securities	$	18,993	$	103,807	$	—	$	—	$	122,800
U.S. Government agency securities	2,330		6,437		31,986		—		40,753
Mortgage-backed securities issued by U.S. Government agencies	—		—		27,725		83,681		111,406
Mortgage-backed securities issued by U.S. Government sponsored enterprises	1		1,471		615,334		1,997,862		2,614,668
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	—		—		17,355		1,142,504		1,159,859
State and municipal securities	115		—		—		—		115
Corporate debt and other debt securities	—		—		15,000		2,000		17,000
Total amortized cost	$	21,439	$	111,715	$	707,400	$	3,226,047	$	4,066,601

Fair Value
U.S. Treasury securities	$	18,993	$	101,640	$	—	$	—	$	120,633
U.S. Government agency securities	2,337		6,455		32,142		—		40,934
Mortgage-backed securities issued by U.S. Government agencies	—		—		27,266		80,678		107,944
Mortgage-backed securities issued by U.S. Government sponsored enterprises	1		1,520		596,366		1,928,958		2,526,845
Collateralized mortgage obligations issued by U.S. Government agencies or sponsored enterprises	—		—		16,855		1,099,593		1,116,448
State and municipal securities	115		—		—		—		115
Corporate debt and other debt securities	—		—		15,186		1,857		17,043
Total fair value	$	21,446	$	109,615	$	687,815	$	3,111,086	$	3,929,962

Schedule of Activity for Available-for-Sale Securities

Proceeds from sales, gross gains, and gross losses on sales of securities available for sale for the six and three months ended June 30, 2018 and 2017 are presented below. The specific identification method is used to reclassify gains and losses out of other comprehensive income at the time of sale. On January 1, 2018, Synovus transferred $3.2 million, at fair value, from investment securities available for sale to other assets upon adoption of ASU 2016-01.



	Six Months Ended June 30,						Three Months Ended June 30,
(in thousands)	2018			2017			2018			2017
Proceeds from sales of investment securities available for sale	$	35,066		$	338,381		$	35,066		$	55,752
Gross realized gains on sales	—			7,942			—			239
Gross realized losses on sales	(1,296		)	(275		)	(1,296		)	(240		)
Investment securities (losses) gains, net	$	(1,296	)	$	7,667		$	(1,296	)	$	(1	)