"Are you really going to buy E2 and convert it into a ska-influenced sushi bar?"
"You can bank on it!"
"Okay, I'll buy up stock in the wasabi producers."
An
English idiom, meaning that one can trust that the referenced statement is correct. Refers to the fact that
banks can be trusted to hold on to huge amounts of
money with a high degree of
reliability.
Ten or twenty years ago, there was probably some good humor to be had by combining the statement "you can bank on it" with the caveat "It's an
S&L."