A global management consulting firm allowed a Democratic contender for the Oval Office to reveal which clients he used to advise on Dec. 9.

McKinsey & Co. confirmed it would allow presidential candidate Pete Buttigieg, 37, to identify the clients he served during the three years he worked as a consultant for the firm between the years 2007 and 2010.

“[Buttigieg] may disclose the identity of the clients he served while at McKinsey from 2007 to 2010,” the firm said in a statement obtained by The Associated Press. “[He must not] disclose confidential, proprietary of classified information obtained during the course of that work or violate any security clearance.”

The decision came after the incumbent mayor for South Bend, Indiana, came under mounting pressure to reveal details of how he raises money for his election campaign and what kind of business he worked in before entering politics.

Buttigieg was one of the Democratic Party’s most successful fundraisers, amassing more than $50 million in 2019 from mostly major donors. In comparison Sen. Elizabeth Warren (D-Mass.) and Sen. Bernie Sanders (I-Vt.) have rejected traditional fundraising techniques and instead relied largely on small dollar donations.

Buttigieg had previously avoided releasing details of his fundraising activities and this has become increasingly difficult to do as his campaign fund pool moves into the top tier. His campaign team has denied any secrecy.

“From the start, Pete has said it is important for every candidate to be open and honest, and his actions have reflected that commitment,” Buttigieg Campaign Manager Mike Schmuhl said according to the Associated Press.

Fellow presidential candidate and former Vice President Joe Biden is the only other Democrat candidate who regularly discloses the status of his fundraisers to reporters.

Warren also succumbed to political pressure that she reveal how much money she made as an attorney. Her campaign team confirmed that the senator had received about $1.9 million in legal fees from nearly 40 out of 60 cases she advised on dating back to the 1980s.

“[The list includes] all the income she earned from each case that we have been able to determine from public records, Elizabeth’s personal records, and other sources,” campaign spokeswoman Kristen Orthman told The Associated Press.

Some of her many clients included Dutch financial institution Rabobank, which became a creditor in the Enron bankruptcy, former directors of Getty Oil who were involved in Texaco’s bankruptcy, and women whose allegations of health issues were jeopardized when former silicone breast implant maker Dow Corning filed for bankruptcy in 1995.

These cases stated Warren served as a consultant, mediator, or expert witness in addition to being counsel. Her largest known payment was nearly $187,000 for a case filed in 1995.

“[Warren] represented a well-known chain of department stores to make sure that it could stay alive and pay its creditors,” Orthman said. “Elizabeth succeeded and the company continued to employ people across its many stores.”