dividends or distributions of more than 25% are subject to 'special' rules for ex-dividend dates. The major difference here is that for these larger distributions or dividends, the ex-dividend date is set as the day after payment
Effective September 5, 2017, the U.S. Securities and Exchange Commission shortened the settlement cycle for transactions in U.S. equities from trade date plus three business days (T+3) to T+2 (Rule 15c6-1(a) under the Securities Exchange Act of 1934 (17 CFR 240)). Common stock acquired in trades settled prior to the ex-dividend date will be entitled to receive the dividend.