Coinbase has revealed the U.S. Commodity Futures Trading Commission (CFTC) subpoenaed it in an unknown matter through an email sent to its users this week and obtained by CryptoSlate.

The email does not provide extensive information about what the financial regulator might be investigating. However, Coinbase said it was requested to provide information about its users’ account and their transaction activity.

Coinbase furthered that its users do not have to take any action, adding that it may respond to the request before Nov. 30 unless it receives a “motion to quash or other objection” filed against the subpoena.

Meanwhile, observers have suggested that the email might be impacting Coinbase users who have interacted with Bybit in the past, indicating a possible connection to rival platform Bybit and its CEO, Ben Zhou.

Alice Comfy, the CIO of Shinoji Research, explained that the subpoena might be the regulator’s method of determining if ByBit had U.S. users. Comfy added:

“This is a clever way of determining that ByBit had US users (previous attempts were less sophisticated), which can then lead to CFTC action similar to what Binance & BitMEX went through. I imagine ByBit will end up in relatively more trouble given they tolerated it longer.”

Bybit is a cryptocurrency exchange founded in 2018 and headquartered in Dubai, United Arab Emirates. According to its website, it has more than 15 million users worldwide and does not serve restricted markets like the U.K. and the U.S.

Coinbase, Bybit, and CFTC have yet to respond to CryptoSlate’s request for comment as of press time.

Regulatory actions continue in the US.

The subpoena reflects several federal agencies’ recent ongoing regulatory actions against crypto-related firms.

Last week, the CFTC, the Department of Justice (DOJ), and the U.S. Treasury scored a significant legal victory against Binance. The exchange agreed to a more than $4 billion settlement with the U.S. authorities, with its founder Changpeng ‘CZ’ Zhao resigning as CEO after pleading guilty to money laundering charges.

Major stakeholders, including Coinbase CEO Brian Armstrong and Kraken’s co-founder Kraken Powell, have argued that this enforcement action would bring more sanity to the emerging industry.