Former Wells Fargo Chairman and CEO John Stumpf sold $61 million worth of Wells Fargo (WFC) shares in the month prior to settling a long-running investigation that charged the bank with falsifying millions of customer accounts to boost sales and fees.

The following month, when regulators announced on Sept. 8 that they’d fined Wells Fargo $185 million for falsifying more than 2 million customer accounts to meet aggressive sales goals, the company’s stock price plunged and Stumpf was called on the carpet before Congress before finally resigning this week.

Stumpf pocketed $26 million in proceeds from that August sale -- the shares in question were “incentive stock options” purchased at a discount to Wells Fargo’s current market price and then immediately sold at a profit -- reflecting a small piece of the rich incentive pay that Stumpf collected during his tenure at the top of the bank.

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However, the sale also raises a red flag of potential violation of insider trading rules that prohibit company insiders from profiting on stock purchases and sales based on unpublished corporate information, said Chicago securities lawyer Andrew Stoltmann.

“At minimum, the optics are horrific for Stumpf and for Wells Fargo,” Stoltmann said. “I would be shocked if the Securities and Excgange Commission doesn’t look heavily into this.”

There is no clear-cut definition for insider trading, said corporate governance consultant Nell Minow, vice chairman of ValueEdge Advisors. However, a significant stock sale by the top executive so close to the announcement of a massive fraud in the bank’s branches would almost assuredly trigger an SEC investigation, she noted. Such sales would normally be restricted by a company’s board of directors, she said.

The SEC declined to comment on whether the agency has instigated an insider trading investigation.

It was not Stumpf’s first significant stock sale of the year, however. According to the bank’s filings with the SEC, Stumpf disposed of 303,012 shares in March 2016, generating $15.1 million, and he sold another 1.42 million shares in May, reaping a $23.9 million profit on the $71.8 million sale.

Altogether, Stumpf sold nearly 3 million Wells Fargo shares in 2016, which is almost 10 times the 351,991 shares he sold the previous year, according to SEC filings. His profit on the 2016 sales amounted to $65.4 million.

In these 2016 stock transactions, Stumpf was able to sell Wells Fargo shares for between $48.91 and $50.51. Wells Fargo’s stock has slid since the news broke in September about the false accounts. The shares now sell for $44.38 – about 10% less than the price immediately prior to the revelations of wrongdoing and a loss of $25 billion in market value for Wells Fargo shareholders.

Wells Fargo said in a statement to CBS MoneyWatch that Stumpf’s stock sales and option exercises “were done in compliance with the company’s pre-clearance approval process for executive officers and did not involve any open market sales or purchases.”

The bank further stated that Stumpf “used shares he owned to pay the company the exercise price for the options exercised and the company withheld shares for taxes. resulting in a net increase in his common stock holdings.” Indeed, Stumpf still owns 2.4 million Wells Fargo shares, currently worth around $108 million.

“John used shares he owned to pay the company the exercise price for the options exercised and the company withheld shares for taxes, resulting in a net increase of his common stock holdings.”

Wells Fargo has previously said that it did not believe the regulatory settlement was a “material event.” The company fired some 5,300 employees for improper conduct over the five year period that the improper activity occurred.