Warren Buffett says the Trump tax cuts passed late last year were a huge win for him and his company, Berkshire Hathaway (BRK-A, BRK-B).

“Berkshire’s gain in net worth during 2017 was $65.3 billion, which increased the per-share book value of both our Class A and Class B stock by 23%,” Buffett wrote in his latest letter to Berkshire Hathaway shareholders.

“Over the last 53 years (that is, since present management took over), per-share book value has grown from $19 to $211,750, a rate of 19.1% compounded annually,” he said. “But 2017 was far from standard: A large portion of our gain did not come from anything we accomplished at Berkshire. The $65 billion gain is nonetheless real — rest assured of that. But only $36 billion came from Berkshire’s operations. The remaining $29 billion was delivered to us in December when Congress rewrote the U.S. Tax Code.”

In its annual report filed alongside Buffett’s letter, Berkshire details exactly how it got to the $29 billion tax bill-related benefit.

“Upon the enactment of the[Tax Cuts and Jobs Act of 2017], we recorded a reduction in our deferred income tax liabilities of approximately $35.6 billion for the effect of the aforementioned change in the U.S. statutory income tax rate. As a result, we recorded an income tax benefit of approximately $29.6 billion and we increased regulatory liabilities of our regulated utility subsidiaries by approximately $6.0 billion for the portion of the deferred income tax liability reduction that we will be required to, effectively, refund to customers in the rate setting process. We also recognized an income tax charge of approximately $1.4 billion with respect to the deemed repatriation of the accumulated undistributed post-1986 earnings of our foreign subsidiaries. Thus, upon the enactment of the TCJA, we included a net income tax benefit in our 2017 earnings of approximately $28.2 billion.”

Back in May 2017 at the most recent Berkshire Hathaway annual meeting, Buffett had hinted at how a potential tax cut could impact the bottom line of the company.

“The deferred taxes that are applicable to unrealized gains on securities would all be applicable to us,” Buffett said during Berkshire Hathaway’s annual shareholders meeting. “We have $90 or $95 billion in gains, and our owners, dollar for dollar, will participate in that… If the rate were to drop 10%, that $9.5 billion is real.”

In the end Berkshire’s gains from tax cuts ended up being far larger.

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Myles Udland is a writer at Yahoo Finance. Follow him on Twitter @MylesUdland

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