LT Cap Gains distributions from Mutual Funds, and shown/entered in box 2a of the 1099-DIV also will automatically be transferred in the background, by the software to Line 13 in the schedule D before going to line 7 of the form 1040 (BUT, the Sched D may not be generated or used at all if your only reported gains are those 2a amounts, and have no other financial transactions requiring the Schedule D, or form 8949)
No basis is need for that since it is taken care of internally within the Mutual Fund's financial accounting following IRS rules in effect for how the Funds are required to report the gains.
____________*Answers are correct to the best of my knowledge when posted, but should not be considered to be legal or official tax advice.*
