Meet the secretive banker behind Warren Buffett's latest deal

BDT Capital PartnersByron Trott, Founder of BDT Capital Partners, in the lobby of the Wrigley BuildingWhen Warren Buffett's Berkshire Hathaway bought 38.6% of the Pilot Flying J truck stop chain on Tuesday, it did so with the help of a firm you've probably never heard of: BDT Capital Partners.

That's by design. Despite having more than $12 billion in assets under management, the merchant bank doesn't even have a public-facing website.

It does, however, have more than 150 employees spread out over four offices in Chicago, New York, London, and Frankfurt, who advise extremely wealthy clients with family-owned businesses.

The firm intentionally flies under the radar to court these billionaires - like Buffett, the Waltons, and the Webers, to name a few - who value privacy.

Byron D. Trott, a midwest native who founded BDT, still helms the company from its Chicago headquarters inside the historic Wrigley Building.

Here's how Trott went from a small-town football player to an investment banker advising billionaires: