(Reuters) - Berkshire Hathaway Inc said on Monday it has taken a $943 million stake in insurance brokerage Aon Plc and sold large portions of its investments in Chevron Corp and Wells Fargo & Co.

The changes were disclosed in a regulatory filing detailing Berkshire’s U.S.-listed holdings as of March 31.

Berkshire also shed two smaller holdings entirely, Canada’s Suncor Energy Inc and private label credit card issuer Synchrony Financial Inc.

The sales suggest that Buffett and his investment managers Todd Combs and Ted Weschler may be growing more wary of valuations as stocks regularly set new highs.

Berkshire sold $6.45 billion of equities and bought just $2.57 billion in the quarter. It ended March with a near-record $145.4 billion of cash and equivalents.

Buffett is “likely shoring up reserves” for a major acquisition, said Doug Kass, a principal at Seabreeze Partners Management LLC in Palm Beach, Florida. “He is clearly in no rush and is sitting on his hands, awaiting the right pitch.”

At Berkshire’s May 1 annual meeting, Buffett said his Omaha, Nebraska-based company would like to spend $70 billion or $80 billion, but would probably not get a chance until the market offered better values.

Berkshire did not immediately respond to a request for comment to Buffett’s assistant.

The Aon investment extends Berkshire’s bet on insurance brokerages, including a stake in Marsh & McLennan Cos that it boosted in the first quarter.

Aon is awaiting regulatory approvals to buy Willis Towers Watson Plc for about $30 billion and create the world’s largest insurance brokerage, ahead of Marsh.

Berkshire has long been known for its insurance holdings, which are overseen by Vice Chairman Ajit Jain, and include Geico auto insurance, General Re reinsurance, and a unit that insures against major and unusual risks.

The sale of 51% of Berkshire’s stake in Chevron represented an unusual reversal. Berkshire had disclosed a new $4 billion stake only in February, and Buffett even said at the annual meeting that the oil company benefited society.

“I have no compunction … in the least about owning Chevron,” Buffett said. “And if we own the entire business, I would not feel uncomfortable about being in that business.”

Less surprising was Berkshire’s revelation that it owned just $26.4 million of Wells Fargo stock, down from $1.58 billion in December and about $32 billion in early 2018.

Buffett was displeased with the bank’s response to address a series of scandals over how its employees treated customers. Berkshire has owned Wells Fargo since 1989.