SEC yield vs. distribution yield

Two yields, two questions: what did it pay, versus what is it earning now?

Trailing distribution yield answers 'what did this fund actually pay over the past year, relative to today's price?' It is backward-looking, includes every distribution type (some of which may be return of capital), and is the figure this site labels Yield TTM.

SEC 30-day yield answers 'what is the portfolio earning right now, after expenses?' — a standardized calculation the SEC requires, based on the last 30 days of portfolio income. For bond funds it approximates the forward-looking earning rate; for option-income funds it can be far below the distribution yield because option premium is not 'income' in the SEC formula.

Neither is wrong — they answer different questions. Comparing funds requires using the same measure for both, and knowing which one a website (including this one) is showing.