plain and simple.... why pay taxes 3-4 months early? you also have to have a 3 day settlement...which by selling now, less stress and they just do it and get it over with... no thinking.
if your CPA says sell 3 mil shares by this time frame to take care of all your taxes... are you going to ask him why? After all, you hired him to figure out the best way... so would you question him? you just do it... and be done.
You are second guessing their motives when it explained to you why they sold... read the remarks.
BTW - how do you know that this is his only income? he may have other businesses but this is most liquid.
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