His secret formula for the stock market is a combination of extreme value and extreme discipline, and so far it’s a winning combination.

From his home office in Broomall, Alpha Architect CEO Wesley Gray tripled the assets under management to $522 million last year, according to a report in The Wall Street Journal by Chris Dieterich.

The Marine veteran is no stranger to gruesome conditions, and his stock selection strategy for Alpha Architect aims to find cheap stocks that other investors are afraid to own, then hold them for the long haul. It’s a formula of math and behavior algorithms that’s part of what’s known as quantitative investing.

“Investors’ willingness and ability to deal with grim death and stick with it makes value investing work,” Gray said.

Alpha Architect also follows the lead of nearby Vanguard in cutting out distributors to keep costs low.

Read more about Alpha Architects and its five available ETFs in The Wall Street Journal here.