A 21-year-old Bank of America Merrill Lynch intern died of an epileptic seizure that may or may not have been brought on by the long hours he was working at the US investment bank, an inquest heard Friday.

Moritz Erhardt, from Germany, died August 15 toward the end of his summer internship at the bank in London. His death raised questions about the culture of long hours in the financial industry and resulted in Bank of America Merrill Lynch launching a continuing review of working practices, especially among junior staff. Erhardt had been working through the night in the days leading up to his death.