If you adequately identify the shares you sold, you can use the adjusted basis of those particular shares to figure your gain or loss.

 

  You will adequately identify your mutual fund shares, even if you bought the shares in different lots at various prices and times, if you:

  1. Specify to your broker or other agent the particular shares to be sold or transferred at the time of the sale or transfer, and
  2. Receive confirmation in writing from your broker or other agent within a reasonable time of your specification of the particular shares sold or transferred.

 

  You continue to have the burden of proving your basis in the specified shares at the time of sale or transfer.