Based on your financial expertise, provide your response or viewpoint on the given financial question or topic. The response format is open.

At what price are dividends re-invested?
Keep in mind the ex-dividend date is different from the payable date (the day the dividend is paid). That means the market price will already have adjusted lower due to the dividend. Short answer: you get the lower price when reinvesting. So here's Vanguard's policy, it should be similar to most brokers: When reinvesting dividends, Vanguard Brokerage Services combines the   cash distributions from the accounts of all clients who have requested   reinvestment in the same security, and then uses that combined total   to purchase additional shares of the security in the open market.   Vanguard Brokerage will attempt to purchase the reinvestment shares by   entering a market order at the market opening on the payable date. The   new shares are divided proportionately among the clients' accounts, in   whole and fractional shares rounded to three decimal places. If the   total purchase can't be completed in one trade, clients will receive   shares purchased at the weighted average price paid by Vanguard   Brokerage Services.