| | December 31, 2017 | December 31, 2016 |
| In millions of COP | ||
| Balance at the beginning of the year | 1,581,689 | 1,505,046 |
| Acquisitions | 92,102 | 29,034 |
| Sales/Write-offs | (71,955) | (72,682) |
| Classified to Assets held for sale | - | (29,008) |
| Gains on valuation (1) | 55,573 | 149,299 |
| Balance at the end of the period(2) | 1,657,409 | 1,581,689 |
| (1) | See note 24.4. Other operating income. |
| (2) | Between December 31, 2016 and 2017 there were no transfers in and out of Level 3 fair value hierarchy related with investment properties. See Note 29 Fair value of assets and liabilities. |
| Type of asset | Balance at the beginning of the year | Appraisals | Net increase (decrease) in investment properties | Adjusted fair value at the end of the year (1) |
| In millions of COP | ||||
| Buildings | 1,355,717 | 49,721 | 7,847 | 1,413,285 |
| Lands | 225,972 | 5,852 | 12,300 | 244,124 |
| Total | 1,581,689 | 55,573 | 20,147 | 1,657,409 |
| Type of asset | Balance at the beginning of the year | Appraisals | Net increase (decrease) in investment properties | Classified to assets held for sale | Adjusted fair value at the end of the year (1) |
| In millions of COP | |||||
| Buildings | 1,275,566 | 52,543 | 27,608 | - | 1,355,717 |
| Lands | 229,480 | 96,756 | (71,256) | (29,008) | 225,972 |
| Total | 1,505,046 | 149,299 | (43,648) | (29,008) | 1,581,689 |
| (1) | Corresponds to the change in the commercial estimate of real estate due to the change in the consumer price index (IPC). |
| | | December 31, 2017 | December 31, 2016 | December 31, 2015 |
| | | In millions of COP | ||
| Income from rentals | | 77,964 | 66,838 | 89,389 |
| Operating expenses due to: | | | | |
| Investment properties that generated income through rentals | | 21,012 | 21,254 | 11,693 |
| Investment properties that did not generate income through rentals | | 2,295 | 2,495 | 2,539 |