From LinkedIn to Facebook: the incredible client list of Wall Street's most secretive firm

Some of the biggest names in tech, telecom, and the media industries have one thing in common.

The tiny financial advisory firm quietly advising them on deals behind the scenes: Allen & Co.

The firm was one of only three banks that worked on $26.2 billion sale of LinkedIn to Microsoft. Along with Qatalyst Partners, it advised LinkedIn on the deal - one of the largest the tech industry has seen in years.

That's just the latest in a long line of landmark roles for the firm. It has previously worked on deals for the likes of Facebook and Google.

The firm shuns the spotlight. It has no website (this one belongs to a different company), and employs fewer than 200 people.

Herbert Allen Jr. led the company for years, and has a seat on the board of Coca-Cola. His son Herb Allen III, who is now CEO at the firm, was named on Vanity Fair's new establishment list in 2012.

Many of the deals the company works on are birthed during the firm's secretive annual Sun Valley Conference, which is sometimes described as the "Billionaire's Summer Camp." Hollywood celebrities mingle with CEOs like Bill Gates and Elon Musk.

Here is a list the firm's best-known clients.

Data and numbers regarding deals and Allen & Co.'s clients in part courtesy of Dealogic.

Disclosure: Allen & Co. was an early investor in Business Insider.