The cameras and lights were all trained on President Obama, as he delivered a stern message in downtown Manhattan about the need for reform in the finance industry.

There was no cheering section. The audience offered up only one round of applause, and a scan of the faces as the president spoke — grimacing, staring at the floor, nervously glancing at BlackBerrys — spoke volumes about how they felt as they listened to the president’s words.

“We will not go back to the days of reckless behavior and unchecked excess that was at the heart of this crisis, where too many were motivated only by the appetite for quick kills and bloated bonuses,” the president warned.

“Those on Wall Street cannot resume taking risks without regard for...