They are not leaving money on the table. You can get in and out of 1K or 10K positions quickly and easily. Someone with 1MM shares cannot. If they dump all at once, it tanks. So, they have to get out gradually. Riding it to the point of reversal isn't leaving money on the table, it's maximizing return. If you start selling once the downtrend is in place, it will do down a LOT faster and ASP will be lower.