How do you get that number?
Missling paid $1.60 a share for the 232,000 shares he acquired. And that money didn't come out of his pocket.
In fact he sold enough shares to have $1,339,310 cash leftover after paying the $800,000 for the 500K shares.
That will much more than cover the taxes involved, so Missling now has 232,000 shares and a chunk of cash in his wallet.
Assuming a tax rate of 50% Missling needed to sell 150,000 shares to pay for the 500K and has $400,000 cash for the taxes.