EnerTeck has incurred net losses since the merger with Gold Bond and, therefore, has no tax liability. The net deferred tax asset generated by the loss carry-forward has been fully reserved. The cumulative operating loss carry-forward is approximately $23,000,000 at December 31, 2016, and expires beginning in 2023.
Deferred income taxes consisted of the following at December 31, 2016 and 2015:
| 2016 | 2015 | |||||||
| Deferred tax assets: | ||||||||
| Net operating loss carry forwards | $ | 7,932,000 | $ | 7,118,000 | ||||
| Other asset differences | - | 85,000 | ||||||
| Deferred compensation costs and other | 1,696,000 | 1,535,000 | ||||||
| Valuation allowance | (9,628,000 | ) | (8,738,000 | ) | ||||
| $ | - | $ | - | |||||
The change in the valuation allowance for the years ended December 31, 2016 and 2015, was $890,000 and $595,000, respectively.