Every year, some very rich person pays multiple millions at auction to buy a private lunch with Berkshire Hathaway Inc.'s Warren Buffett. This year, the anonymous winning bidder paid $2.68 million. Crazy, right? Those who missed out on the chance to dine with the Oracle of Omaha likely comforted themselves with the thought that such a lunch is just wretched excess—it couldn't actually be worth $2.7 million.

Or could it? A rather creative Deutsche Bank report argues that the meal could be a great long-term investment—even for the hoi polloi who watch the annual bidding as entertainment. It's quite simple when you have fun with the math (and reality). The exercise starts with the average U.S. worker, which the report describes as a 42-year-old with savings of $92,500, earning an annual 7 percent. (We wish.) By age 65, even if that person contributed no additional money to the pot, it would have swelled to $284,000, after adjusting for inflation, the report claims.

"But when, over dessert, Warren whispers the secret to Berkshire Hathaway’s 19 per cent annualised return since inception, the expected pot becomes $3.8 million," the report reads. "Hence the average American should be willing to pay $3.5 million for the lunch." Coincidentally, last year's auction winner paid $3,456,789.Bottom line: " If someone with just $92,500 to invest should spend that much, every billionaire hedgie who has dined with Warren has underpaid."

Whether the hedgies of yore—former winner David Einhorn of Greenlight Capital among them—got a steal for their millions or not, it's all for a good cause. The money goes to the Glide Foundation, a San Francisco charity that serves meals to the homeless, hosts support groups through its women’s center for abuse victims, and provides treatment for drug addiction.

This article was provided by Bloomberg News.