(Reuters) — Warren Buffett’s Berkshire Hathaway on Monday revealed a new stake in Apple in a bet that the stock’s price could rebound after iPhone sales fell for the first time.

Berkshire held 9.81 million Apple shares worth $1.07 billion as of March 31, according to a regulatory filing detailing most stock holdings of Buffett’s Omaha, Nebraska-based conglomerate.

It is unclear whether the Apple investment was made by Buffett or by one of his portfolio managers, Todd Combs and Ted Weschler, who each invest about $9 billion.

Buffett typically makes Berkshire’s multibillion-dollar investments, while Combs and Weschler make smaller wagers.

The investment deepens Berkshire’s commitment to the technology sector, which Buffett has largely shunned apart from a big stake in International Business Machines Corp, which grew slightly in the first quarter.

Apple last month reported its first quarterly decline in revenue in 13 years as an increasingly saturated market hurt iPhone sales.

Chief Executive Tim Cook is looking to develop other technologies, and last week unveiled a $1 billion investment in Chinese ride-hailing service Didi Chuxing.

Shares of Apple have fallen by nearly one-third since April 2015. They were up $2.13, or 2.4 percent, at $92.65 in Monday morning trading, likely because of Berkshire’s imprimatur.

“The stock is stunningly cheap, and it has a massive pile of cash,” said Steve Wallman, founder of Wallman Investment Counsel in Middleton, Wisconsin, who has owned Berkshire since 1982 and Apple since 2003. “Apple is not getting credit for research and development it is doing behind the scenes, which will eventually show up in new products.”

An Apple spokeswoman did not immediately respond to requests for comment.

Despite his aversion to technology sector, Buffett told CNBC on Monday, he offered to help Dan Gilbert, the chairman of Quicken Loans and owner of the Cleveland Cavaliers basketball team, finance a bid for Internet company Yahoo.

Reuters first reported Buffett’s support on Friday.

The Apple investment may have been made with proceeds from the sale of AT&T stock, as Berkshire exited what had been a $1.6 billion stake in the quarter.

Berkshire’s investment also puts it at odds with investors that have retrenched from Apple.

Last month, billionaire activist investor Carl Icahn said he sold his entire Apple stake, on concern that China could make it harder for the company to do business there.

David Tepper’s Appaloosa LP also shed his Apple stake in the first quarter, while Ray Dalio’s Bridgewater Associates cut its investment by two-thirds.

In Monday’s filing, Berkshire also reported higher stakes in Bank of New York Mellon Corp, Deere & Co and Visa, and lower stakes in MasterCard and Wal-Mart Stores.

(Reporting by Jonathan Stempel in New York; Additional reporting by Ross Kerber in Boston; Editing by Lisa Von Ahn and Steve Orlofsky)