Sen. Elizabeth Warren (D-Mass.) earned nearly $2 million working as a consultant for corporations and financial firms while she was a law professor at Harvard University, the University of Pennsylvania and other law schools, according to records her campaign abruptly released Sunday evening.

Warren’s consulting work often involved companies dealing with bankruptcy, which was her specialty as an academic. Her campaign had been asked repeatedly for the information and had declined to release it multiple times.

Her work for some of the companies doesn’t fit neatly with her current presidential campaign brand as a crusader against corporate interests.

For instance, the documents released Sunday show that Warren made about $80,000 from work she did for creditors in the energy company Enron’s bankruptcy and $20,000 as a consultant for Dow Chemical, a company that was trying to limit the liability it faced from silicone breast implants that were made by a connected firm.

Earlier this year, Warren had released a list of about 50 cases that she worked on, but the descriptions of the work were at times misleading and the amount of income and dates for her work were not included.

While the cases released by Warren’s campaign stretch over more than three decades, the figures disclosed Sunday show that nearly all of the money was made from cases filed after she got her job at Harvard in 1995. (Warren was elected to the Senate in 2012.)

The income includes about $212,000 for representing Travelers Indemnity Co. in 2009, and $190,000 for what her campaign described as representing a chain of department stores owned by PA Bergner & Co. in the mid-1990s.

Warren’s campaign did not release compensation information for all of the cases, reporting in some instances — including a case involving First Commercial Bank — that “the campaign has no compensation records for this case.”

In other cases, Warren’s campaign said, she did work for companies pro bono.

Kristen Orthman, a campaign spokeswoman, did not immediately say why the campaign released the information Sunday.

“We have updated that disclosure to include 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,” she said in a statement.

The disclosure comes as a rival for the Democratic presidential nomination, South Bend, Ind., Mayor Pete Buttigieg, has escalated his attacks on her, demanding that she release tax returns from the years when she consulted for companies.

Warren’s decision to release the information revealed the extent to which Buttigieg and Warren are eyeing each other as direct rivals in the large Democratic field. Though they represent different points on the ideological spectrum — with Warren appealing to liberals while Buttigieg is favored by moderates — surveys show that the two are competing for similar voters in Iowa, namely, college-educated whites.

“In order to credibly call out the president’s corruption, you’ve got to be prepared to lead by example on transparency, and that does mean disclosing your tax returns from both public and private-sector work,” Buttigieg said at a recent campaign stop.

Warren, in turn, has asked him to name his clients from his time as a consultant at McKinsey & Co. and demanded that he open his fundraisers to the media.

Late last week, Buttigieg released a summary of some of the work that he did for McKinsey, but he has not released the names of his clients. He has cited as the reason a nondisclosure agreement he signed while at McKinsey.

Warren released the income summary hours after a campaign event in South Carolina, where she dinged unnamed primary opponents “who have decided to finance their campaigns by doing closed-door fundraisers, sucking up to the corporate executives, the millionaires, the billionaires.” The line appeared aimed at Buttigieg.

Warren, who typically has avoided attacking other primary candidates, called Buttigieg out by name last week, saying he should release the names of his major fundraisers.

However, speaking to reporters in Charleston on Sunday night, Warren declined to say whether there was reason to believe Buttigieg had been making promises to donors behind closed doors.

“I’ve talked about this for the last couple of days, answering a lot of questions about it, and I really don’t have anything to add that I haven’t already said,” ­Warren said.

Amy B Wang in Charleston contributed to this report.