The holding company of Berkshire Bank is expecting to take a write-down of $21 million in the fourth quarter of 2017 due to a recalculation of its deferred tax assets triggered by the new tax law, the company said in a statement.

Berkshire Hills Bancorp performed an analysis to determine the impact of the revaluation of the net deferred tax assets using the bank’s Sept. 30 balance of $39 million, and included an estimate of the deferred tax impact from the recent acquisition of Commerce Bancshares Corp., which it completed this year.

All banks are confronting this one-time write down as a result of the way net deferred tax assets are accounted for on the balance sheet.

Large banks are facing a similar fate. Citigroup, for example, has said the company could be looking at a $17 billion write-down due to its deferred tax assets.

The revaluation of Berkhsire’s net deferred tax assets is subject to further clarifications of the new law that cannot currently be estimated. As such, the company is unable to make a final determination of the impact on the quarterly and year to date earnings for the period ending Dec. 31 at this time.

The DTA-related write down is a one-time event and banks still expect the benefits of tax reform to far outweigh this initial setback.