A brighter future is in store for bank stocks, according to the Oracle of Omaha.

Already the largest shareholder in Bank of America Corp. and Wells Fargo & Co., Warren Buffett's Berkshire Hathaway Inc. has taken up a new 1.07% stake in the biggest U.S. bank, JPMorgan Chase & Co., putting it among the bank's top 15 owners.

The third-quarter move to buy up 35,664,767 of JPMorgan shares, as well as 6,087,319 shares in PNC Financial Services Group Inc., expands Berkshire's portfolio even further into the banking sector. By the end of September, Buffett had swelled Berkshire's holdings in banks to be 21% larger than they were as of June 30.

"[The third quarter] was an opportunity to get into some solid franchise names," said CFRA Senior Director Cathy Seifert, in an interview. "It looks to me like he's setting up a portfolio that's going to be a barbell between technology and financials."

Bank stocks have largely seen a downturn throughout 2018, which could have presented Buffett with a dip to expand Berkshire's presence in the industry, analysts said. As of Nov. 15, the SNL U.S. Bank and Thrift Index was down 6.06% in 2018.

Berkshire's year-old position in Bank of America grew by 29.2% in the third quarter, while its stakes in U.S. Bancorp and Bank of New York Mellon Corp. expanded by 24.1% and 20.1%, respectively. The insurance giant's long-standing investment in Wells Fargo dipped 2.1% from the second quarter, as Berkshire's ownership stake in the bank continues to hover just below the 10% ownership threshold that, if breached, would require it to become a bank holding company. Berkshire's position in M&T Bank Corp. held steady at 5,382,040 shares from June 30 to Sept. 30.

The move into JPMorgan's stock comes as Buffett's ties to Jamie Dimon, the bank's chairman and chief executive, continue to deepen.

In 2018, the two executives have penned op-eds together and launched a healthcare venture with Amazon.com Inc. Earlier in the year, Buffett also expressed regret about not having Berkshire invested in JPMorgan, which he said at the time was one of the handful of stocks he owns personally.

"We have had a pretty heavy weighting in banks right along. But I should have bought JPMorgan," Buffett said in an interview with Yahoo Finance in March. "It's a terrifically run operation."

Historically, Berkshire holds onto its newly acquired stocks for sizable periods of time, all while expanding its stake in those companies. That is why CFRA's Seifert believes Berkshire's stake in JPMorgan may grow from here, which could come at the expense of the company's position in Wells Fargo.

"It's a higher quality name," Seifert said of JPMorgan.

Berkshire's exposure to the financial sector is not exclusive to banking, though.

The company stretched its stake in Goldman Sachs Group Inc. by 38.5% during the third quarter, while also taking up a new position in property-and-casualty insurer Travelers Cos. Inc. Berkshire's other insurance investment, Torchmark Corp., remained flat at 6,353,727 shares between June 30 and Sept. 30.

The Travelers investment was particularly notable for Barclays analyst Jay Gelb, who wrote in a Nov. 14 research report that Berkshire's stake in the company will likely be passively managed as he believes it was established by one of Berkshire's investment managers, not Buffett himself.

Several of the companies that Berkshire took a position in during the third quarter saw share-price gains promptly after the investments were publicly released.

On Nov. 15, the day after Berkshire's investments were disclosed, Travelers' shares rose 2.07%, JPMorgan's stock climbed 2.55% and PNC's shares increased 1.91% on the day. The S&P 500 was up just over 1%.