The Democratic Party is giving two prominent business leaders speaking roles at the party convention: CarMax co-founder Austin Ligon and Costco co-founder Jim Sinegal along with Newark Mayor Cory Booker.

A party official says the businessman will make the case for why President Barack Obama should keep command of the U.S. economy. Their selection aims to put a dent in Republican Mitt Romney’s assertions that he is best equipped to help businesses prosper, in part because of his private sector experience.

Democrats say Newark Mayor Cory Booker will also speak at the convention, which starts Sept. 4. Booker’s selection indicates a thaw with the Obama campaign after he criticized the president for targeting Romney’s record at a private equity firm. He is expected to introduce the party platform to convention delegates.

Booker chairs the Platform Committee. “We have a platform that will excite not just Democrats but the nation … and ensure that Barack Obama will be re-elected,” Booker said during a C-SPAN broadcast of committee deliberations.

Other convention speakers announced Friday include Philadelphia Mayor Michael Nutter and Los Angeles Mayor Antonio Villaraigosa.

The Associated Press contributed to this report