[crazygringo]

That's certainly a tricky question which essentially is connected to their "insider information", but the answer certainly doesn't rely on limiting others' ability to sell.

Solutions to that generally involve long-term vesting periods for executive shares, e.g. executives can't sell their shares for some extended period of time that is sufficiently "long-term". If the board really made sure incentives were aligned, ideally it would be some period of years after they left the company, so they could never sell while they were in a position to influence the value of shares.

But again, there is absolutely zero reason that should ever apply to someone without insider information, i.e. investors generally.