It’s likely that all these executives get part of their compensation in the form of stock. In many cases this is given, then has a vesting schedule where you don’t actually get access to it for a year or two or three. This serves a couple purposes. One is tie their compensation to the stock… pay for performance, and another is to keep people around, as they would have to forfeit the stock which hasn’t vested if they decide to leave… the old golden handcuffs.

Part of my compensation is like this, just on a smaller scale.

In talking with a financial advisor, they said to treat this like a normal part of my compensation. Rather than leave it all in the company stock, which would leave me extremely overweighted in one stock, it was best to sell it and apply the funds according to whatever my broader more diversified strategy is.

September is a common time for this stuff to happen. So the stock finally vested, as it does every year, and they sold it, like they probably do every year (this is public record, you can check), so they can diversify their holdings.