A group of digital asset companies backed the U.S. Commodity Futures Trading Commission (CFTC) in a legal clash over its authority to regulate perpetual futures for individual stocks.

Coinbase Global COIN, Kalshi, Kraken’s parent company Payward, DRW Holdings, Jump Trading and Paradigm filed a letter in support of the CFTC with the United States District Court for the Southern District of New York in a lawsuit brought by the Capital Markets Alliance (CMA) earlier this month.

The CMA sought to challenge the CFTC’s approval of open-ended futures contracts for stocks, comparable to those in the cryptocurrency derivatives market. The CMA said it is backed by prominent traditional finance firms, including broker-dealers such as Cboe and Citadel Securities.

Coinbase, Kalshi and Payward have all submitted applications to list U.S. stock perps, which were deemed approved on Nov. 2.

Perpetual futures are derivatives contracts allowing traders to bet on the future price of an asset. Unlike traditional futures, they have no expiry date.

The CMA argued that such products for equities would fall under the jurisdiction of the Securities and Exchange Commission (SEC).

A CFTC spokesperson described the action as “troubling” in an email to CoinDesk when the CMA filed the lawsuit on Nov. 3.

“Our markets should be governed by law, not litigation campaigns intended to block innovation,” the spokesperson added.