> Clearly not true. In 2020, the SEC fined Andeavor for buying back its own stock while negotiating a potential merger. The duty is to affected shareholders and the integrity of the market, not the company.

No, no, you can still construct scenarios where it's legal. But yes, buybacks are especially heavily regulated. And yes, you have a fiduciary duty to shareholders. (But not to the 'integrity of the market'. There might be some duties and vague laws there, but it's not a fiduciary duty.)

In any case, what specifically are you referring to that's "clearly not true" in my comment? I constructed some examples that deliberately avoid a company (or an employee of said company) buying their own stock.

> Don't know how you got this from Matt Levine. Isn't his catchphrase "Everything is securities fraud"?

He has more than one catch phrase. The relevant one here is that insider trading in American law is about misappropriating information and fiduciary duty. Which he contrasts to French law amongst others, which is about fairness and a level playing field.

However, regulators in the US often want to spin the rules to be about fairness, but courts so far mostly disagree.

One example he brought up was: suppose you work for Bank X and you take the train in the morning to work. You overhear an employee of Bank Y talking about some deal on the phone (and that other guy doesn't notice you). You have no fiduciary duty to Bank Y.

By French law, you couldn't trade on the information you gained.

But by American (and UK law, where the example was from) your fiduciary duty to your employer, Bank X, might even compel you to use the information to their advantage. Especially if you were on company time when you overheard the conversation.