By Jason Zweig April 21, 2023 11:01 am ET

Meet the stock pickers who pick stocks once and then stop—for a quarter of a century.

Tiffany Gray, 22 years old, is a senior majoring in finance and wealth management at Delaware State, a historically Black university in Dover, Del. Jonathan Rivers, 20, is a junior double-majoring in environmental sciences and religious studies at the University of Virginia. 

Ms. Gray and Mr. Rivers, along with their peers, will assemble a portfolio of perhaps 15-20 stocks and lock it in place for the next 25 years. 

That sounds crazy, and maybe it is, but investors of all ages can learn from these young people.

They are part of an extremely long-term experiment created by Thomas Gayner, chief executive of Markel Corp., a Glen Allen, Va.-based insurance company. Mr. Gayner has run Markel’s investment portfolio since 1990, building it up to $22 billion with a patient, conservative approach.

He has established a student investment fund at each of the two universities. By the year 2047, Mr. Gayner’s family will contribute, in 25 annual installments, a total of $750,000 to the two clubs. 

The students—29 of them this year at Virginia, nine at Delaware State—will use that money to pick investments that will be frozen for the next 25 years. Each year, the members will buy another round of picks for the next quarter-century. No one, no matter what, will ever be able to sell anything. 

Starting in year 26, the members who picked the stocks 25 years earlier will disburse half the accumulated money for scholarships; the other half will be reinvested for the future by that year’s members.

Interviewing these students this week, I was struck by how they call each other “analysts” and by how they refer to their potential holdings as “businesses” and “companies,” not as “stocks.”

Says Ms. Gray at Delaware State: “We have to look beyond what might happen in just the next one or two years, to three years, five years, 10, 25, even 50 years. We’re not scared of the long term. It’s an inspiration.”

Mr. Rivers at Virginia says, “If we can think about investments in a way that most young people don’t and that even most professional investors think of as a huge challenge, that’s just an incredible opportunity.”

One lesson from these new clubs is old: the astonishing power of letting your winners run for as long as possible. You can’t lose more than 100% on even your biggest losers (unless you bought them with borrowed money), but the potential gains on your biggest winners are boundless.

From the beginning of 1993 through this Feb. 28, for instance, 58 stocks gained more than 10,000% apiece, according to the Center for Research in Security Prices. Ten returned more than 25,000%.

These “superstocks” include now-familiar giants Apple Inc., Qualcomm Inc. and Monster Beverage Corp.—but also such minnows as air-conditioning firm AAON Inc., tobacco-and-real-estate holding company Vector Group Ltd. and kitchen-equipment maker Middleby Corp.

Going even further back, the mutual fund known today as Voya Corporate Leaders Trust was formed in 1935 with a portfolio of 30 stocks frozen in place. Thanks to a handful of huge winners, its long-term performance has been outstanding, although its annual expenses of 0.49% are steep for a fund that does literally nothing.

The key is not selling. In a 1984 article called “The Coffee Can Portfolio,” veteran investor Robert Kirby described a client’s husband, who had exactly copied all the buy recommendations Mr. Kirby’s firm had made to his wife, putting about $5,000 in each. 

Unlike her, however, the husband had ignored all the sell recommendations. He’d never sold a share. Several of his holdings grew to more than $100,000 apiece. One, which became Xerox Corp., surpassed $800,000, greater than the value of his wife’s entire portfolio. 

The long-term tailwind from letting your winners run is easy to underestimate; the human mind isn’t built to extrapolate giant growth rates over multidecade periods.

To capture every possible big winner, you could buy a total stock-market index fund—although it will make some trades. Or you could directly buy every stock in the total market and then freeze—and never make another trade.

If you wanted to spread a total of $10,000 across most of the 4,000-plus companies in the Dow Jones U.S. Total Stock Market Index, online brokerage Interactive Brokers would let you do that in a “basket trade,” commission-free. You could hold the entire basket permanently, never selling any of its component stocks, and see what happens.

The students in Mr. Gayner’s investment clubs already understand the awesome power of compounding.

“If we and our successors can pick only a few winners, they’ll drive the returns, and our losers won’t matter,” says Joe Beck, 22, who helps run the University of Virginia student fund. 

All this echoes an idea Warren Buffett often espouses: Imagine you could make only 20 investments in your entire lifetime. You’d be forced to understand whatever you buy, to focus on only a few opportunities and to hold them as long as possible.

Another leader of the Virginia club, Jacob Slagle, 21, says, “It really forces you to think of businesses in a different way: Can it survive 25 years?”

Omar Parker, Jr., a 20-year-old member of the Delaware State club, is already thinking beyond the year 2048: “When we’re long gone,” he says, “our fund will be a legacy to the future generations.”

Write to Jason Zweig at intelligentinvestor@wsj.com

Appeared in the April 22, 2023, print edition as 'How to Pick a Stock For the Year 2048'.