	R$ thousand
	Amortized cost	Gross unrealized gains	Gross unrealized losses	Fair value
Brazilian government securities	101,822,760	1,881,077	(422,079)	103,281,758
Corporate debt securities	40,875,928	836,715	(1,734,013)	39,978,630
Bank debt securities	1,251,066	169,142	(236,355)	1,183,853
Brazilian sovereign bonds	719,494	27,326	(18,693)	728,127
Foreign governments securities	3,210,554	175	(8,182)	3,202,547
Marketable equity securities and other stocks	11,302,834	620,896	(885,923)	11,037,807
Balance on December 31, 2017	159,182,636	3,535,331	(3,305,245)	159,412,722

Brazilian government securities	58,484,065	1,323,156	(609,193)	59,198,028
Corporate debt securities	43,821,686	1,011,275	(2,690,253)	42,142,708
Bank debt securities	1,626,211	121,745	(188,913)	1,559,043
Brazilian sovereign bonds	395,626	7,319	(1,731)	401,214
Marketable equity securities and other stocks	9,966,872	389,291	(538,602)	9,817,561
Balance on December 31, 2016	114,294,460	2,852,786	(4,028,692)	113,118,554

	R$ thousand
	On December 31, 2017		On December 31, 2016
	Amortized cost	Fair value	Amortized cost	Fair value
Due within one year	31,635,369	31,167,067	12,690,168	11,905,872
From 1 to 5 years	83,579,399	83,816,085	60,071,806	60,251,675
From 5 to 10 years	16,004,079	16,363,350	19,677,065	18,994,970
Over 10 years	16,660,955	17,028,413	11,888,549	12,148,476
No stated maturity	11,302,834	11,037,807	9,966,872	9,817,561
Total	159,182,636	159,412,722	114,294,460	113,118,554

Financial instruments pledged as collateral and classified as available for sale, totaled R$ 59,482,796 thousand and R$ 64,275,415 thousand in 2017 and 2016, respectively, as disclosed in Note 23 "Financial Assets Pledged as Collateral".

In 2017, the Organization maintained a total of R$ 4,391,259 thousand (2016 - R$ 5,517,516 thousand) financial assets available for sale pledged as a guarantee for liabilities.

We have applied our policy for impairment testing described in Note 2(f)(viii)(b) and in 2017 there was objective evidence of loss registered in financial assets available for sale in the amount of R$ 1,729,039 thousand in 2017 (2016 - R$ 2,106,107 thousand and 2015 - R$ 424,522 thousand), included in Note 9.

21. Financial assets available for sale