The author is a Reuters Breakingviews columnist. The opinions expressed are his own.

“Where are the customers’ yachts?” The age-old question is often addressed to Wall Street, but it could be the turn of Boston mutual-fund giant Fidelity Investments to respond. An exclusive venture-capital vehicle affiliated with Fidelity sometimes competes with its public funds for technology and biotech investments, a Reuters investigation has found. That means the likes of Abigail Johnson, the chief executive of the firm founded by her father, may occasionally benefit at the expense of the mutual-fund group’s clients.

The VC fund, F-Prime Capital, has Johnson family members and top Fidelity fund managers among its investors. That doesn’t need to be a problem. What doesn’t look good, though, is that F-Prime’s early-stage investments in some companies whose value later rocketed may have prevented Fidelity’s mutual funds buying in because of ownership limits.

One example is Ultragenyx Pharmaceutical. The VC fund made about 10 times its initial $11 million investment, according to Reuters. Fidelity mutual funds bought in a couple of years later, but at a far higher price. Funds marketed to the public typically have limited capacity to invest in unlisted companies, but they usually have some. And in this case, BlackRock and Vanguard mutual funds did get into Ultragenyx earlier, at lower prices.

Fidelity’s mutual funds also bought in at around the time that F-Prime sold its interest in Ultragenyx. That could be a coincidence. Nonetheless, one of the largest, market-moving fund managers on the planet might prefer to avoid another such instance lest there be any concern that the public funds’ timing boosted the returns of the Johnsons and other insiders.

There’s also the question of whether it’s sensible to hand top mutual-fund managers interests in a vehicle whose fortunes will, at times, be at odds with those of the investors whose money they are managing. Even as a way to retain top performers, that’s open to question.

F-Prime’s funds are advised by Impresa Management, which is responsible for about $2.6 billion, according to filings reviewed by Reuters. That’s tiny relative to Fidelity’s $2.1 trillion under management. And the Johnsons are entitled to invest beyond Fidelity’s public funds. Yet keeping it entirely outside the Fidelity corporate family might be cleaner. As things stand, the CEO’s task is to ensure both the reality and perception of fairness. On this count, Johnson has explaining to do.