The bid for havens also saw traders boosting bets on Fed interest-rate cuts, fully pricing in a quarter-point move by June.

The Federal Reserve governor said it is healthy to examine the regulatory architecture, but stressed the importance of the central bank having insight into the banking system.

For bond investors who'd been piling into Treasuries over recent weeks, Wednesday's Fed policy announcement offered vindication.

Chair Jerome Powell repeated the central bank is not in a hurry to adjust borrowing costs. Officials can wait for greater clarity on the impact of policies.

Fresh tariffs from the Trump administration, paired with retaliatory action from US trade partners, have fanned Americans' expectations for future inflation.

Summers said a combination of major immigration restrictions, federal government layoffs and damage to US competitiveness from President Donald Trump's tariffs.

The bond market in the past month has been caught between signs that US economic growth is slowing.

He also reiterated that he and Trump are focused on bringing down 10-year Treasury yields, rather than on the Fed's short-term benchmark rate.

Thirty members of the Senate Banking and House Financial Services committees signed a letter petitioning the administration to name a new vice chair for supervision — and quickly.

Notably, Trump described the January decision to hold rates steady – which looks set to be the Fed's stance for some time — as "the right thing to do."