There is an option on many reports to use the Sale Date as opposed to the Gift Date if that is the issue. If not, as long as you sell all shares within a reasonable amount of time you could 'average' the sale prices as long as your stock gains & losses are correct. I would definitely track each separate sale in the notes of the gift though. Another option would be to go back and adjust the initial gift to relect the first number of shares sold and add a new gift (using the old gift date, etc.) for the balance and continue doing this process until all shares are sold. I like this option for the audit trail and sale dates, etc.

My question is,

1. is the donor transferring all the shares to you at once,

  1A.Put the stock gift in as the mean on the day the stock transferred.  Then, when all the shares are sold, take the exact amount and enter in the as sold amount. 

 OR

 2. are they making a $$amount pledge to be fullfilled over time with multiple gifts of stock?

     2A.  Put the mean value against the pledge each time, and put the exact sold amount for each payment/multiple payments.