Suppose one has $300,000 in taxable gains consisting of stock held a long time.
Realizing the entire $300,000 would result in a large tax bill and higher tax prepayments in the current and the following year as well a higher tax rate and other charges such as Medicare.
So would it be better to only realize $150,000 or $100,000 of capital gains for the current taxable year?
There is the option trying to postpone the capital gains as long as possible at the expense of holding stocks that don't show much future prospects.