Just days after Equifax Inc. discovered it had been hacked, three executives sold off $1.8 million worth of shares, a move that would avoid the price plummet that followed the credit bureau's public disclosure of one of the largest data breaches in U.S. history.

Equifax has maintained the executives were unaware of the breach, which the company said it learned about on July 29, when they made those trades on Aug. 1. Still, published reports about the stock sales raise “fundamental questions,” two partners at the law firm Dorsey & Whitney said in an article published Friday at the Harvard Law School Forum on Corporate Governance and Financial Regulation.

“Under Equifax's insider trading policy, was there a mandatory pre-clearance policy requiring the executives to get approval prior to placing their sell orders? If so, why were the sales approved in light of the existence of a data breach? Did Equifax invoke a blackout period as soon as it knew of the data breach and, if not, why not?” Dorsey & Whitney partners Cam Hoang and Gary Tygesson, both in Minneapolis, said in the article.