CHICAGO — Anxiety-prone investors looking for safety in the stock market have sometimes found it in so-called widows-and-orphans stocks. At their best, they pay dividends for decades and bounce around a bit less when the markets convulse, as they have over the last week. For years, AT&T was the textbook example. Procter & Gamble was another.

But it is rare to meet actual orphans with stock portfolios, let alone ones who have hung on to their investments for nearly half a century.

After Barnaby Dinges lost his father at age 7 and his mother at 9, a stranger, Sanford Kovitz, volunteered to keep an eye on his money. A young father himself, Mr. Kovitz had heard about the situation and thought he could help.

Nearly 50 years later, the two are still at it, having shepherded Mr. Dinges’s portfolio through private school, college, parenthood, divorce and assorted hiccups and triumphs