Bank Regulators to Lean on Enforcement as High Court Hits Rules

A pair of US Supreme Court decisions curtailing the rule-writing authority of federal regulators will likely force banking agencies to rely on their supervisory and enforcement powers to police Wall Street.

The high court on Monday ruled that any new entrant to a market has six years from the time they’re able to sue to challenge a regulation they oppose, exposing a broad universe of existing rules to new legal fights. That came just days after the justices overturned a long-standing doctrine deferring to regulators on interpreting ambiguous laws.

The decisions are set to crimp high-profile financial rules, including stricter ...