Berkshire Hathaway Inc. shares rose on Wednesday after its board gave its billionaire chairman, Warren Buffett, more freedom to conduct stock buybacks, which the conglomerate has not done since 2012.

Class A shares of Berkshire gained $10,305, or 3.6 percent, to $298,805 in morning trading, while Class B shares rose $7.47, or 3.9 percent, to $197.88 on the New York Stock Exchange.

The gains followed Berkshire's announcement late Tuesday that Buffett and Vice Chairman Charlie Munger, who make major decisions on allocating capital, may now repurchase stock when both believe the price is below Berkshire's "intrinsic value," a determination that would be made "conservatively."

Berkshire's old buyback policy prohibited buybacks when the stock price exceeded 1.2 times book value per share, or assets minus liabilities. The Omaha, Nebraska-based company's stock had been trading at closer to a 1.4 times multiple.

With the change, Buffett can spend more of Berkshire's cash and equivalents, which totaled $108.6 billion as of March 31, after having for 2-1/2 years been unable to complete what he calls "elephant" sized acquisitions of whole companies.

"We're surprised that this took so long," wrote Meyer Shields, an analyst at Keefe, Bruyette & Woods who has a "market perform" rating for Berkshire.

Shields called the old buyback policy "almost obsolete," saying the recent slashing of the U.S. corporate tax rate materially boosted book value by reducing Berkshire's deferred tax liabilities, but "with almost no impact on intrinsic value."

Berkshire will not conduct buybacks under the new policy before releasing second-quarter results, scheduled for Aug. 3.