I currently hold stocks that pay dividends, which I reinvest in the stock. I have not personally sold anything, so do I have to report anything?

I own just a few SMP 500 stocks which I have received dividends for, and reinvested back in the stock. I know I have to report them on my tax return if I sell them, but I'm not sure if I have to in this case. Also, I didn't receive a form 1099-b, so I'm not sure how I would in the firts place.