**Coinbase Challenges SEC's Proposed Rule Changes**

Coinbase has submitted a third letter to the SEC, critiquing the agency's proposed changes to the definitions of a national securities exchange. Coinbase's chief legal officer, Paul Grewal, argues that the SEC lacks the necessary information to perform a proper cost-benefit analysis, relying instead on irrational arguments.

Grewal points out that the SEC's proposal is flawed due to its unclear definition of "crypto asset security" and the number of exchanges in the market. He suggests that decentralized exchanges (DEXs) would struggle to meet the proposed disclosure requirements.

The SEC's proposal, which has been in the works since 2022, has faced criticism from various industry groups and lawmakers. Coinbase urges the SEC to withdraw the proposal and conduct thorough research before proceeding.