If you are asking about reinvested dividends. Dividends are taxable. You will get a 1099 Div for those.
A reinvested dividend is taxable. It is really 2 transactions, you got a Dividend then you bought more shares. Just like if they sent you a check and then you bought more shares. So be sure to add it to your cost basis when you sell the shares.
Unless it is in some kind of retirement account like a 401K or IRA. Then you should not get a 1099Div for it and it is not reported or taxable.
