Warren Buffett's Berkshire Hathaway Inc. on Wednesday said it had taken stakes in JPMorgan Chase & Co., Oracle Corp. and Travelers Cos., as the conglomerate puts some of its large cash hoard to work.

As of Sept. 30, Berkshire owned about $4.02 billion of stock in JPMorgan, the largest U.S. bank by assets, where one of Buffett's investment managers, Todd Combs, is a board member.

Berkshire said it also owned about $2.13 billion of Oracle stock and $460 million of Travelers stock.

The holdings were disclosed in a regulatory filing detailing Berkshire's U.S.-listed stock investments as of Sept. 30.

The JPMorgan investment closes a notable hole in Berkshire’s stock portfolio, which already contained large investments in other financial services companies, including American Express Co, Bank of America Corp, Goldman Sachs Group Inc, US Bancorp and Wells Fargo & Co.

Buffett has long praised the leadership of JPMorgan Chief Executive Jamie Dimon, and over the last year partnered with him and Amazon.com Inc Chief Executive Jeff Bezos to create a new company aiming to cut U.S. employee healthcare costs.

Atul Gawande, a surgeon and critic of medical industry practices, was named in June to lead the venture.

Buffett, Combs and another portfolio manager, Ted Weschler, handle Berkshire’s investments.

While the filing did not say who bought which stocks, larger investments are normally made by Buffett, who often buys stock when he cannot find whole businesses to purchase.

Those stocks include Apple Inc, in which Berkshire said earlier this month it had a $57.6 billion stake.

Berkshire has more than 90 units in the insurance, energy, food and retail, industrial, railroad and other sectors. But Buffett has not completed a major acquisition since January 2016.

Despite the stock purchases, Berkshire ended September with $103.6 billion of cash and equivalents.