Sen. Bernie Sanders (I-VT) criticized Hillary Clinton throughout the Democratic primary for giving lucrative speeches to Wall Street. Perhaps it's no surprise then that he's deeply disappointed President Barack Obama has accepted a $400,000 check from investment firm Cantor Fitzgerald LP to speak at a health care conference in September. 

"I think at a time when people are so frustrated with the power of Wall Street and the big money interests... it is unfortunate that President Obama is doing this," Sanders said in an interview on "CBS This Morning" Friday. 

"Wall Street has incredible power, and I would have hoped that the president would not have given a speech like this," he added.

Fellow progressive Sen. Elizabeth Warren (D-MA) shared similar views on Thursday, saying she feels "troubled" by Obama's decision. 

President Obama earned $400,000 annually during his two terms in office. Eric Schultz, senior advisor to President Obama, cited pivotal legislation in his defense. 

"He recently accepted an invitation to speak at a health care conference in September, because as a president who successfully passed health insurance reform, it’s an issue of great importance to him," Schultz told The Independent Tuesday. 

"With regard to this or any speech involving Wall Street sponsors, I’d just point out that in 2008, Barack Obama raised more money from Wall Street than any candidate in history—and still went on to successfully pass and implement the toughest reforms on Wall Street since FDR," he added. 

Watch: