McKinsey & Co. has said it would give former employee and current Democratic presidential candidate Pete Buttigieg permission to reveal the clients with whom he worked during his time with the consulting firm.

McKinsey & Co.'s list of clients has been controversial at times, including a stint working with ICE and Enron, and Elizabeth Warren has been pushing her primary opponent to release the information. The firm said on Monday that he could disclose his client list during his time at the company—2007 to 2010—provided he not "disclose confidential, proprietary of classified information obtained during the course of that work, or violate any security clearance."

"The bulk of my work on these teams consisted of doing mathematical analysis, conducting research, and preparing presentations," Buttigieg has said. "I never worked on a project inconsistent with my values, and if asked to do so, I would have left the firm rather than participate."

Warren has also been pushing Buttigieg to open his fundraising events up to reporters, which he said he will also do. The South Bend Mayor's campaign has been surging of late, with polls showing him leading in the early voting states of Iowa and New Hampshire, and he has a lot of resources on hand. That is thanks in part to raising funds from big money donors. Warren, as well as Sen. Bernie Sanders, have been relying on small money donors instead.

Buttigieg, for his part, has said Warren should release a more comprehensive list of her own clients from her time working as a corporate lawyer. She released data on Sunday saying she had been paid approximately $2 million for legal work spanning three decades.