Coinbase and the U.S. securities regulator faced off in a federal appeals court in Philadelphia on Monday as the cryptocurrency exchange presses the agency to create new rules for digital assets. Coinbase, the largest U.S. crypto exchange, sued the Securities and Exchange Commission last year in an effort to compel the regulator to act on a petition for rulemaking it filed in 2022. In that petition, it urged the SEC to provide clarity on the circumstances under which a digital asset is a security and create a new market structure framework that is compatible with cryptocurrencies.