US banks are testing their own cyber defenses after federal banking supervisors called lenders to ask what they knew about the $6.3 billion hack at Binance, according to people familiar with the matter.

The calls came from staff at the Federal Reserve and the Office of the Comptroller of the Currency (OCC), which supervises national banks. The outreach began on Monday morning, with supervisors asking lenders whether they had seen unusual transactions or any disruption to their services, Reuters reported on November 5.

Binance, the world's largest crypto exchange, disclosed the theft last week. People familiar with the matter described it as the largest financial heist on record. The episode underscores why the queries reach beyond the crypto industry itself: with more banks now offering digital-asset services and exchange partnerships, supervisors are checking whether trouble at a crypto firm can spill into the regulated banking system.

BREAKING: The FED and the OCC have contacted US banks to assess potential security risks following Binance's $6,300,000,000 hack. Banks are checking for unusual activity and possible service disruptions.

— Litest (@Litest) November 5, 2026

https://x.com/Litest/status/2118307556632227972?ref_src=twsrc%5Etfw

How Banks Are Responding

At least one bank that received a call said its operations had not been interrupted. Staff prepared talking points in case customers asked about the hack, though few questions have come in so far.

The cybersecurity team at one of the largest US banks contacted Binance within hours of the breach and is now writing an internal report on the attack. That report will feed into a review of the bank's own systems and could lead to security upgrades. It is not yet clear whether the bank would be exposed to the same methods the attackers used.

Other lenders are also studying the incident, running diagnostics to determine whether their defenses could stop a similar attack.

One person familiar with the matter said fast-improving artificial intelligence models are the main worry for bank security teams, because such tools make it harder for banks to stay ahead of attackers. Banks are putting large amounts of resources into reviewing and fixing their cybersecurity code, the person added.

Bank shares have shown little sign of strain so far.

What Binance and Regulators Have Said

The Fed and the OCC declined to comment. The contacts with banks have so far been informal inquiries, not formal examinations. The distinction matters because formal examinations give supervisors broader access to bank records and can end in required corrective actions.

The checks come after US bank regulators eased rules on crypto activity. President Donald Trump has publicly supported digital assets. The Fed, for example, withdrew a 2022 policy that required banks to get regulatory permission before starting crypto-related activities. Since then, more lenders have built out digital-asset services.

Stephan Mühlbauer, head of US government affairs at CertiK, said the inquiries could lead to closer checks on banks. He pointed to crypto custody services, counterparty risk and incident-response systems as likely areas of focus.

"The authorities' job is to protect the financial system," Mühlbauer said. "They need to understand where risks are concentrated and how quickly they can respond."

Whether the inquiries develop into the closer checks he described is the next development to watch as the response to the breach unfolds.

Binance said it was not aware of the talks between banks and their supervisors, and that it knew of no impact on US lenders.

"We are in close contact with regulators all over the world, keeping them up to date on this security breach," a company spokesperson said.

The exchange said it has shared an incident report with all of its partner banks, but has not yet determined how the breach affected those banking partners. That unresolved question remains the main gap in the picture so far.