I remember when Workday (WDAY) had its expiration coming up and there was a lot of speculation the stock would tank that day. The float was pretty small before

I remember when Workday (WDAY) had its expiration coming up and there was a lot of speculation the stock would tank that day. The float was pretty small before the lockup and the thought was because of this the price was very inflated. It went down the first 10 minutes of trading but shot right back up as large buyers were waiting to see the price action that day and bought it up. The stock is up 75% or so since the lockup 2 years later. If it were as easy as shorting IPO's (or going long PUTS) near lockup, I'd be a billionaire. As you've pointed out - it's impossible to know what will happen, if anything (making a spread unplayable too) when the lockup expires.