Though Mr. Romney left Bain in early 1999, he received a share of the corporate buyout and investment profits enjoyed by partners from all Bain deals through February 2009: four global buyout funds and 18 other funds, more than twice as many over all as Mr. Romney had a share of the year he left. He was also given the right to invest his own money alongside his former partners. Because some of the funds and deals covered by Mr. Romney’s agreement will not fully wind down for several years, Mr. Romney is still entitled to a share of some of Bain’s profits.

During his political career, Mr. Romney has promoted his experience as a businessman while deflecting criticism of layoffs caused by private equity deals by noting that he left Bain in 1999. But records and interviews show that in the years since, he has benefited from at least a few Bain deals that resulted in upheaval for companies, workers and communities…

But since Mr. Romney’s payouts from Bain have come partly from the firm’s share of profits on its customers’ investments, that income probably qualifies for the 15 percent tax rate reserved for capital gains, rather than the 35 percent that wealthy taxpayers pay on ordinary income. The Internal Revenue Service allows investment managers to pay the lower rate on the share of profits, known in the industry as “carried interest,” that they receive for running funds for investors…

But the family’s Bain holdings are still considerable: in his 2011 disclosure, Mr. Romney reported Bain assets between $12.4 million and $60.9 million, which provided between $1.5 million and $9.3 million in income. The blind trust for his wife, Ann, held at least another $10 million, generating income of at least $4.1 million. Because the campaign is required to provide only a minimum value for some Bain assets now held by Mrs. Romney, the total could be far more.