Schwab's confirmation statement for me in 2021 had this information:
The tax deduction for donating shares held for more than one year is generally the fair market
value of the shares on the date of the contribution. The deduction for donating shares held for one year or less is generally limited to the lower of cost basis or the fair market value on the date of contribution. Please consult your tax advisor for specifics on your own tax situation.
IMHO: gain or loss does not matter; it's just the dollar value of your contribution.
