In the company's application to the Federal Reserve, it was revealed that Buffett's personal stake, just over 2 million shares, combined with that of Berkshire's now exceeds 10 percent, "due to subsequent share repurchases by Wells Fargo."
As a result, "Berkshire is seeking permission to retain its current ownership position... and to acquire additional shares of common stock of Wells Fargo for investment purposes, although Berkshire does not have any specific transaction or dollar value in mind with respect to any such potential purchases."
The company said, however, that it "routinely assesses market conditions and may decide to purchase additional shares of common stock of Wells Fargo based on its evaluation of the investment opportunity presented by such purchases."
Berkshire added that it "anticipates that any such purchases would be on the open market at prevailing market prices."
The firm currently owns the largest stake in Wells Fargo, with about 9.45 percent of shares outstanding, according to FactSet.
The Federal Reserve exerts special oversight when investors take large bank stakes.
In a September 2008 policy statement, the Fed said it often lets investors take double-digit bank stakes not designed to exert a "controlling influence," but would review any resulting business relationships "case-by-case."
The U.S. Treasury Department, meanwhile, has said it will not deem a 10 percent stake to result in "control" of a big bank if an investor agrees in writing to limits on its involvement.
— CNBC's Alex Crippen and Reuters contributed to this report.