What is the ex-dividend date?
It is the first day a stock trades without its next dividend. To receive the dividend you must buy the shares before the ex-dividend date, at the latest at the close of the trading day before it. If you buy on or after the ex-dividend date, the seller gets the dividend instead.
What is the difference between the record date and the pay date?
The record date is the day the company checks its list of shareholders to see who gets the dividend; in the US it is usually the same day as the ex-dividend date. The pay date is when the money actually arrives in shareholders' accounts, often a few weeks later.
Why does the price usually fall on the ex-dividend date?
From that day a new buyer no longer gets the dividend, so the shares are worth roughly the dividend less. The price typically opens lower by about the dividend amount, so buying just before the ex-date only to collect the dividend does not make money by itself.
How is the yield calculated?
Yield is the yearly dividend per share divided by today's share price, as a percentage. A company paying $1 a quarter ($4 a year) with a share price of $100 has a 4% yield.
Where do the dates come from?
Dates from Nasdaq's dividend calendar, for stocks listed on Nasdaq. Companies can change them, so check the company's announcement before trading.