Any capital gains till that moment are not taxed. Gains from selling assets are taxed. Normally when someone sells an asset, even a minute before they die, they owe 20% capital gains tax. The annual income of the moguls of the day  $1.3 million for William Astor; $576,000 for Cornelius Vanderbilt  was listed in the pages of The New York Times in 1865.) That may seem like a lot, but Buffett ranks as roughly the world's sixth-richest person  he's worth $110 billion as of Forbes' estimate in May 2021.
All capital gains till that moment are not taxed.
( z0 tax :ARG3 ( z1 gain :mod ( z2 capital ) :mod ( z3 all ) :time ( z4 until :op ( z5 moment :mod ( z6 that ) ) ) ) :polarity - )
(z0 / tax-01
    :ARG3 (z1 / gain-01
              :mod (z2 / capital)
              :mod (z3 / all)
              :time (z4 / until
                        :op1 (z5 / moment
                                 :mod (z6 / that))))
    :polarity -)
All capital gains till that moment are not taxed .
z1 :mod z2
z1 :mod z3
z1 :time z4
z5 :mod z6
z4 :op1 z5
z0 :polarity 0
z0 :ARG3 z1