this is from IRS PUB 550
Payments in lieu of dividends. If you borrow stock to make a short sale, you may have to remit to the lender payments in lieu of the dividends distributed while you maintain your short position. You can deduct these payments only if you hold the short sale open at least 46 days (more than 1 year in the case of an extraordinary dividend, as defined later) and you itemize your deductions. You deduct these payments as investment interest on Schedule A (Form 1040). If you close the short sale by the 45th day after the date of the short sale (1 year or less in the case of an extraordinary dividend), you cannot deduct the payment in lieu of the dividend you make to the lender. Instead, you must in-crease the basis of the stock used to close the short sale by that amount.
To determine how long a short sale is kept open, do not include any period during which you hold, have an option to buy, or are under a contractual obligation to buy substantially identical stock or securities.
If your payment is made for a liquidating distribution or nontaxable stock distribution, or if you buy more shares equal to a stock distribution issued on the borrowed stock during your short position, you have a capital expense. You must add the payment to the cost of the stock sold short.
Exception. If you close the short sale within 45 days, the deduction for amounts you pay in lieu of dividends will be disallowed only to the extent the payments are more than the amount you receive as ordinary income from the lender of the stock for the use of collateral with the short sale. This exception does not apply to payments in place of extraordinary dividends.
Extraordinary dividends. If the amount of any dividend you receive on a share of preferred stock equals or exceeds 5% (10% in the case of other stock) of the amount realized on the short sale, the dividend you receive is an extraordinary dividend.
there is an issue in Turbotax. with desktop there is forms mode which would allow you to enter the dividend paid, when appropriate, as an adjustment to the gain/loss using code B in the Capital Asset Sale Worksheet.
I could not find the adjustment column except in forms mode
