NEW YORK (Reuters) - Billionaire investor Warren Buffett on Saturday attacked what he saw as tricks used by U.S. companies to boost earnings and stock prices, but he defended one oft-criticized practice: share buybacks.

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“As the subject of repurchases has come to a boil, some people have come close to calling them un-American –characterizing them as corporate misdeeds that divert funds needed for productive endeavors,” Buffett said in his annual letter to shareholders.

“That simply isn’t the case: Both American corporations and private investors are today awash in funds looking to be sensibly deployed. I’m not aware of any enticing project that in recent years has died for lack of capital.”

Some critics, including BlackRock Inc BLK.N Chief Executive Officer Larry Fink, think the practice of companies buying back their own shares to boost earnings has been used to excess.

Repurchasing shares boosts earnings per share by reducing the shares remaining on the market. Critics contend the money can be better used to hire employees or buy equipment.

Buybacks fell to an average $2.3 billion a day during the January-February earnings season, TrimTabs Investment Research Inc data showed on Monday, after spiking to $5.7 billion a day in early-to-mid 2015.

Last month, Fink warned CEOs of S&P 500 .SPX companies in a letter that the world's largest asset manager would be looking for an explanation of how cash from corporate tax cuts touted by U.S. President Donald Trump will be used, especially if it is deployed for buybacks.

Buffett can buy Berkshire’s own shares back at 120 percent or less of book value, but that has “proved hard to do,” Buffett said.

“Our buying out ‘partners’ at a discount is not a particularly gratifying way of making money. Still, market circumstances could create a situation in which repurchases would benefit both continuing and exiting shareholders,” he said. “If so, we will be ready to act.”

ACCOUNTING TRICKS

Buffett was less sanguine on other practices used by public companies, saying “too many” are deviating from generally accepted accounting principles (GAAP) to present better earnings numbers.

Buffett said it “makes us nervous” that companies regularly leave out what they call “restructuring costs” and “stock-based compensation” from their expenses, boosting profits by deviating from standard accounting practices.

“To tell owners year after year, ‘Don’t count this,’ when management is simply making business adjustments that are necessary, is misleading. And too many analysts and journalists fall for this baloney.”