| 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 |
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|
|
|
|
|
| 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 |
Maturity
| 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.