Warren Buffett's Berkshire Hathaway is Wells Fargo's largest shareholder. Image source: The Motley Fool.

Wells Fargo's (WFC -0.41%) fake-account scandal is one thing. But it'd be a whole other issue if the scandal had caused the bank's largest shareholder, Warren Buffett's Berkshire Hathaway (BRK.A -1.17%) (BRK.B -1.27%), to sell its 10% stake in the bank.

Fortunately for all other Wells Fargo shareholders, Buffett didn't do so, confirming in a CNN interview at the end of last week that Berkshire Hathaway hasn't sold a single share of the bank's stock. "It's a great bank that made a terrible mistake," Buffett told CNN's Poppy Harlow. "It was a dumb incentive system, which when they found out it was dumb they didn't do anything about it."

Berkshire didn't offload Wells Fargo shares

Buffett's comments on CNN mirror Berkshire Hathaway's disclosures in its two latest regulatory filings with the Securities and Exchange Commission. At the beginning of November, Berkshire filed its 10-Q, which gives investors a quarterly update on the company's business.

While Berkshire didn't address the Wells Fargo scandal in its 10-Q, it confirmed that, as of Sept. 30, approximately 60% of the conglomerate's common stock portfolio was "concentrated in the equity securities of four companies." Those four companies are American Express, Wells Fargo, International Business Machines, and Coca-Cola.

Data source: CNBC's Berkshire Hathaway Portfolio Tracker. Chart by author.

Reading between the lines, this meant that Berkshire Hathaway hadn't unloaded any of its position in Wells Fargo in the roughly three weeks between the Consumer Financial Protection Bureau's revelation of the scandal on Sept. 8 and the end of that month.

Following Buffett's interview with CNN on Nov. 11, Berkshire Hathaway filed its 13F with the SEC three days later, which discloses its specific stock positions. That document showed that Berkshire holds around 500 million shares in Wells Fargo, unchanged from the prior period.

This undoubtedly came as a relief not only to Wells Fargo, but also to other owners of its stock. Buffett has long championed the bank as one of his favorite investments. He once went so far as to say that if he had to invest all his money into one stock, Wells Fargo would be his choice.

Buffett's imprimatur is significant for any company, but particularly for one that relies so much on trust, as banks do given that they're tasked with keeping depositors' hard-earned money safe. This is why it meant so much to Goldman Sachs and Bank of America when Berkshire Hathaway invested $5 billion into each of them during the financial crisis.

In the interview with CNN, Buffett went on to note that the principal problems that allowed the scandal to balloon were a poorly designed incentive system that encouraged employees to open fake accounts for customers, as well as the fact that Wells Fargo didn't address the problem quickly enough, allowing it to continue for years after executives learned of it.

Wells Fargo claims to be addressing the root causes of the scandal, but for shareholders probably the most important point to note right now is that Buffett sees no reason for unloading the bank's stock.