The risk of a devastating cyberattack may be the single greatest danger to the U.S. financial system, according to J.P. Morgan Chase CEO Jamie Dimon.



J.P. Morgan spends almost $600 million annually to tighten its defenses and ward off a constant stream of attacks, Dimon said Thursday in his annual letter to shareholders. But the interconnected nature of the financial system means the risk never goes away.

Indeed, J.P. Morgan was the victim of a large data breach in 2014 tied to hackers.



"The threat of cyber security may very well be the biggest threat to the U.S. financial system," Dimon said.

The bank spends "a lot of time and effort trying to protect our company in different ways as part of the ordinary course of running the business," Dimon said. "But the financial system is interconnected, and adversaries are smart and relentless — so we must continue to be vigilant."

In last year's letter, Dimon called cybersecurity an "arms race" that was critical for the financial industry, as well as for sectors including utilities and tech firms. He also called for improvements to the local and international regulatory framework tied to cyber risk.

Dimon hints that there seems to be improvements coming. In this year's letter, Dimon said the "good news" is that the banking industry and U.S. government are "increasingly being mobilized to combat this threat."