When, in 1984, Mitt Romney left Bain & Co. to found Bain Capital, it was the beginning of a steady migration that has populated the global private equity industry with hundreds of ex-“Bainies”, many of them in now in charge of major private equity franchises.

As ex-Bain Private Equity Guy Number One, Romney set best practice. He made a fortune with Bain Capital and now has a reasonable shot at taking the White House. Many other ex-Bain private equity people are still in the fortune-building phase.

A search on financial services database Capital IQ reveals that of the thousands of professionals listed as working at “private investment firms” around the world, more than 700 have “Bain & Co” listed in their professional biographies.

Certainly, other types of financial institutions have spawned private equity professionals in bulk. McKinsey bios are everywhere in the industry – Capital IQ counts more than 1,500. But McKinsey is almost three times larger than Boston-based Bain & Co. The term “ex-Goldman” probably turns up the most in private equity (Capital IQ counts more than 2,000), but Goldman Sachs has 10 times the employees of Bain's 2,700 consultants.

One finds within private equity a number of highly influential diasporas. Alumni from the original Citicorp Venture Capital arms on both sides of the Atlantic have been prolific founders of firms. London's 3i, given its long tenure in the market, has been a launching pad for many European private equity careers. Investcorp and Robert Bass alumni seem to have Midas touches. Former employees of the legendary Drexel Burnham Lambert – Michael Milken's longdefunct high-yield empire – are now in dominant positions across Wall Street. But these ex-Drexel pros are a bit like Jedi knights – powerful, but a race marked for extinction.

Then there's the expanding Bain alumni network. There must be something in Bain's water fountains that intoxicates hundreds of consultants with the desire to become value-added equity deployers. What's more, the Bain model of intensively studying and reworking businesses seems to make a natural transition to a private equity format, especially given today's emphasis on improving the operations of portfolio companies, as opposed to applying mere financial engineering (don't get a Bain guy started on this topic).

A recent profile of Mitt Romney that appeared in The New Yorker magazine had an interesting take on Bain's corporate culture, which may go some of the way toward explaining its good fit with private equity as well as the propensity of its alumni to stick together: “[Founder Bill] Bain's idea was to create a more exclusive and mutually beneficial arrangement with his clients. He promised not to work for the competition, and, instead of simply devising a new strategy, he would stick around and help implement it. It was the difference between belonging to a gym and having a personal trainer. Employees read Dress for Success and were sent on Outward Bound-style leadership retreats. Business reporters wondered why Bain consultants all seemed to wear the same red ties. Romney and his colleagues were called Bainies, and, not surprisingly, there were accounts of insufferable young Bainies swarming into a company and confidently reorganizing it as middle managers were brushed aside.”

Setting aside Bain Capital, the US private equity firms founded by ex-Bain & Co. consultants is too long to list here. The Bain swarm has moved beyond US shores, as well. Two of the most significant firms in the most significant buyout markets of Asia, Japan and Australia, are essentially ex-Bain shops. Advantage Partners in Tokyo wears its Bain colours with pride. Three of the four founders of Pacific Equity Partners are ex-Bain including Tim Sims, the former chairman and managing director of Bain & Co's Australasian and African operations. PEP is about to close on somewhere near $4 billion, making it the heaviest hitting local LBO player by a large margin.

Noting the disproportionately large presence of Bainies in private equity, Sims recently explained to me that the consulting firm has “always placed distinctive emphasis on working with management in multi-year relationships to deliver a tangible result.”

Sims continued: “Strategy and delivery sounds trite but is a powerful cocktail. The result is that the really successful Bain graduate carries a blueprint for the skills which are now recognised as setting apart the highest performing funds in the private equity industry.”