Pay czar Kenneth Feinberg believes the compensation paid to Wells Fargo & Co's chief executive for 2009 raises serious questions, he told CNBC on Thursday.

He also said companies that do not fall under his jurisdiction should voluntarily adopt the reforms he is proposing for bailed-out companies.

Feinberg, appointed by President Barack Obama's administration, is in charge of setting compensation levels for top employees at companies that received multiple U.S. bailouts, such as American International Group Inc .

Wells Fargo's CEO, John Stumpf, received compensation worth $21.3 million for last year, according to materials filed with U.S. regulators on Wednesday.

The San Francisco-based bank, fourth-largest in the United States by assets, last year repaid the $25 billion it received from the Troubled Asset Relief Program.

(Reporting by Karey Wutkowski and Elinor Comlay; Editing by Gary Hill)