CNN – JPMorgan Chase CEO Jamie  Dimon told Congress Wednesday that the bank’s massive loss can be blamed on insufficient risk controls and a failure by traders to understand the bets they were placing.

Dimon both defended the bank, which he says will still be “solidly profitable” in the second quarter, and sounded a note of contrition before members of the Senate Banking  Committee.

“We have let a lot of people down,” Dimon said, “and we are sorry for it.”

JPMorgan announced last month that it had suffered a multi-billion dollar loss on trades built around contracts tied to corporate bonds that were originally intended to hedge the bank’s exposure.