OMAHA, Nebraska: Berkshire Hathaway has reshaped its tech portfolio ahead of Warren Buffett's retirement, unveiling a new multibillion-dollar bet even as it continued to pare one of its most famous holdings.

In its latest quarterly filing with the U.S. Securities and Exchange Commission, the conglomerate disclosed a US$4.3 billion stake in Alphabet, equal to 17.85 million shares as of September 30. The investment marks Alphabet's entry into Berkshire's top ten U.S. stock positions.

At the same time, Berkshire further reduced its long-held Apple stake, cutting it to 238.2 million shares from 280 million in the July-to-September period. The company has now sold nearly three-quarters of the more than 900 million Apple shares it once owned, though Apple remains Berkshire's largest holding at $60.7 billion.

The filing detailed Berkshire's U.S.-listed equity positions as of September 30, which accounted for the bulk of its $283.2 billion stock portfolio. Alphabet's arrival is notable given Buffett's longstanding value-first approach and his historical reluctance toward technology stocks. He has often said he views Apple more as a consumer products company.

It remains unclear whether Buffett, portfolio managers Todd Combs and Ted Weschler, or CEO-in-waiting Greg Abel made the specific investment decisions. Buffett typically handles the most significant trades.

The Alphabet purchase also underscores a missed opportunity that the Berkshire leadership once regretfully acknowledged. At the 2019 annual shareholder meeting, Buffett and the late Vice Chairman Charlie Munger openly reflected on not buying Google earlier. "We screwed up," Munger said. "He's saying we blew it," Buffett replied.

Alphabet shares rose 1.7 percent in after-hours trading following the disclosure. Berkshire's new positions often spark investor interest, seen as a kind of endorsement from Buffett.

Berkshire was again a net seller of stocks in the quarter, buying $6.4 billion while selling $12.5 billion, extending a run of 12 consecutive quarters of net selling. Cash rose to a record $381.7 billion. Apple may have represented most of the divestments.

The company also trimmed its holdings in Bank of America, selling six percent of its stake and continuing reductions that began in last year's third quarter. Bank of America remains the group's third-largest holding. Berkshire fully exited DR Horton while adding to positions in Chubb, Domino's Pizza, and several others.

U.S. markets ended mixed on November 14: the Dow slipped around two-thirds of a percent, the S&P 500 finished nearly unchanged, and the Nasdaq made a small upward move.

As Buffett prepares to hand over the CEO role to Greg Abel on January 1, Berkshire's massive cash pile and dealmaking restraint have drawn attention. Analysts say the Omaha-based group has been wary of high valuations, having avoided significant acquisitions for nearly a decade and not repurchased its own stock in over a year.

Berkshire today owns nearly 200 operating companies, including BNSF Railway, primary energy and manufacturing businesses, and well-known consumer brands such as Dairy Queen, Fruit of the Loom, and See's Candies.