(Bloomberg) -- The $10 trillion U.S. corporate bond market has been inflated by companies taking advantage of record low interest rates for the last five years, Securities and Exchange Commission member Daniel M. Gallagher said this week.

“It clearly looks like a bubble,” Gallagher said Wednesday at a market structure conference sponsored by the Security Traders Association. “You have a buildup of assets and you have to think about the downside if the bubble gets pricked.”

Retail investors would be most vulnerable to a sell-off that could result after the Federal Reserve raises interest rates and prices of outstanding bonds fall, Gallagher said at the conference in Washington. Banks have curtailed their fixed-income holdings as they seek to comply with new capital rules and Volcker Rule restrictions on risky bets.