Beer billionaire Jim Koch buys a random stock every 2 weeks - and trusts his former babysitter to execute his trades

• A beer billionaire's investment strategy is to randomly pick a stock to buy every couple of weeks.
• Boston Beer Company's Jim Koch trusts his family's former babysitter to oversee his stock portfolio.

A beer billionaire likes to randomly pick a stock to buy every two weeks — and trusts his family's former babysitter to carry out the trade.

Jim Koch, the 74-year-old cofounder of Boston Beer Company, recently told Forbes about his unusual investment strategy, explaining that he won't even attempt to beat the market through savvy stock selection.

"I don't believe that I have any chance in hell of outsmarting the professional investors," Koch said, noting that if he did buy a stock, whoever sold it to him would probably have more and better information than him. He prefers to focus on running his business, and puts money into stocks not to get richer, but to protect his fortune and diversify his risk, he said.

The entrepreneur added that it would be too much hassle to personally oversee his portfolio. "I don't want to worry about it," he said. "It's boring. It's annoying."

Koch leaves the buying and selling to his wife's assistant, whom they first hired as a babysitter two decades ago. Every fortnight, she cashes in any losing positions, then randomly picks a single stock to buy from a list of indices including the S&P 500 and Russell 2000. The "zero-engagement" strategy has outperformed most actively managed portfolios and requires minimal effort, Koch told Forbes.

The billionaire brewer, whose company's flagship beer is Samuel Adams, started investing in stocks more than 60 years ago. At age 12, he took the money saved from his paper route, and bought two shares of Procter & Gamble for about $140. He's never sold them, and after six stock splits, they've turned into 128 shares worth a total of $20,000 today.

Koch might have a knack for investing, or he may have simply gotten lucky. Either way, he clearly believes that he brings the most value to the beer business, and has no interest in competing with elite investors like Warren Buffett and Carl Icahn.