This isn’t really a tax deduction, but it is a subtraction that can save you a lot of money. And it’s one that many taxpayers miss. If, like most investors, you have mutual fund dividends automatically invested in extra shares, remember that each reinvestment increases your “tax basis” in the fund. That, in turn, reduces the amount of taxable capital gain (or increases the tax-saving loss) when you sell your shares.
Forgetting to include the reinvested dividends in your cost basis—which you subtract from the proceeds of sale to determine your gain—means overpaying your taxes. TurboTax Premier and Home & Business tax preparation solutions include a very cool tool—Cost Basis Lookup—that will figure your basis for you and make sure you get credit for every dime of reinvested dividends.