The courts have interpreted Section 10b of the Securities and Exchange Act as prohibiting insiders from trading in their own company’s shares only if they do so “on the basis of” material nonpublic information. This element of scienter for insider trading liability is sometimes tricky for regulators and prosecutors to satisfy because insiders who possess material nonpublic information at the time of their trade will often claim they did not use that information. The insider may claim that her true motives for trading were entirely innocent (e.g., to diversify her portfolio, to pay a large tax bill, or to buy a new house or boat). Such lawful bases for trading can be easy for insiders to manufacture and are often difficult for regulators and prosecutors to disprove.

Historically, the SEC and prosecutors sought to overcome this challenge by taking the position that knowing possession of material nonpublic information while trading is sufficient to satisfy the “on the basis of” test. This strategy met mixed results before the courts, with some circuits holding that proof of scienter under Section 10b requires proof that the trader actually used the inside information in making the trade.

Facing a circuit split, the SEC attempted…