MetLife shares surged 5.3% to $44.73 by that day's end as investors reacted to the court decision and speculation grew about its implications for other banks and non-banks labeled as systemically important financial institutions by FSOC.

FSOC determination

Attorneys for New York-based MetLife argued in February that FSOC's determination was arbitrary and that the panel — which includes Treasury Secretary Jacob Lew, Federal Reserve Chair Janet Yellen and seven more voting members — hadn't considered the economic effect of subjecting the biggest U.S. life insurer to new capital requirements.

Government lawyers defending the designation had emphasized the insurer's interconnectedness to financial firms around the world and asked Collyer to defer to the "considered judgment" of FSOC's panel members.

MetLife Chief Executive Officer Steve Kandarian had fought the SIFI label, saying his firm is well regulated by state watchdogs and isn't vulnerable to sudden withdrawals like banks.

The escape from SIFI status may free up $2.5 billion or more that could be returned to shareholders, according to John Nadel, an analyst at Piper Jaffray Cos. Kandarian had scaled back share buybacks as federal regulators worked to finalize tighter capital standards for non-bank SIFIs.

'Big win'

"This is a big win for the company, as it removes the SIFI designation and an unknown federal regulatory regime, and also validates a controversial management decision," Ryan Krueger, an analyst at Keefe, Bruyette & Woods Inc., said March 30 in a note to clients.

Kandarian announced in January that the insurer was weighing a possible sale, spinoff or public offering of a U.S. retail operation, which sells variable annuity and life insurance products. He's sticking with that plan even after the court ruling, as the insurer looks to focus on businesses that have lower capital requirements and greater cash-flow generation.