Bezos doesnt disclose his personals, but with the bernie wealth tax he would owe about 9b of his 150ishb. Warren Buffets maybe 6b. Under trumps tax plan, Amazon as a company did not pay taxes in 2017 or 2018, and in 2019 paid $162 million. In 2019 their revenue was about $280b, and about $14b in total profits. Thanks to tax credits and deductions, they paid about 1.2% of the 21% corporate tax rate.

At worst Bezos probably paid a 20% capital gains unless he went directly to an IRA then he would just pay tax on the income generated.