Which Fund Families Give Their Stock-Pickers the Longest Leash?
And what it means for the risk when a manager heads for the door.
Line up the actively managed large-cap funds at Fidelity, MFS, J.P. Morgan, and T. Rowe Price, and the industry’s favorite measure of activeness says they’re quadruplets. Open the portfolios, and they look more like strangers who happen to share a haircut.
One Number’s Blind Spot
Active share, introduced in 2009 by researchers Martijn Cremers and Antti Petajisto, has become the go-to shorthand for how active a fund is. It measures the slice of a portfolio that differs from its benchmark index—one tidy figure that’s easy to rank and easy to screen.
Across 51 actively managed large-blend and large-growth funds at those four firms, the typical active share figure sits in a narrow lane, from about 46% at T. Rowe Price to 54% at MFS, shown below. These are the industry’s most conventional offerings: Big-cap funds from traditional shops. If any corner of the market should look uniform, it’s this one.
The trouble is what active share treats as equivalent. A fund can differ from its prospectus benchmark in very different ways. It can hold the same stocks the index holds at different weights, which is what active share reflects, or it can buy companies outside the index—increasingly, privately held ones. It tells you how much a fund departs from the index. It can’t show you how.
Scoring the Strays
A fuller gauge of activeness would account for what active share leaves out. Consider a simple remedy—call it Morningstar Active Score. Conceptually, it starts with everything active share captures but gives progressively more weight to holdings that sit further from the benchmark. Each percent of assets a fund holds as an overweighting in an index-held stock counts as a point; each percent held in a public company outside the benchmark counts as two; and each point in a privately held company counts as four points. Add up the weighted points and, unlike active share, the total isn’t capped at 100; a fund with large off-benchmark and private stakes can climb well above it. A higher score doesn’t mean a better fund—only one that wanders further from its index, for better or worse.
Where a Fund Really Wanders
Score the four firms this way, and their off-benchmark reach is the first place the tidy active-share cluster cracks.
Activeness Has More Than One Axis
Fidelity’s funds hold an average of about 19% of assets in companies outside their benchmarks—more than double J.P. Morgan and T. Rowe Price, and well above MFS’s 13%. That’s the longest leash of the four: Fidelity’s managers set their funds apart by owning what the index leaves out and differentiating their funds most.
Twins, Until You Look Closer
The cleanest example is a matched pair. Fidelity Blue Chip Growth FBGRX and JPMorgan Large Cap Growth JLGMX are both gargantuan members of the large-growth
Their portfolios say otherwise. Fidelity Blue Chip Growth often keeps nearly 20% of assets in companies outside the Russell 1000 Growth Index—well above the JPMorgan fund’s 13% or so—including international stocks such as Taiwan Semiconductor Manufacturing TSM and Canadian firm Celestica CLS, as of June 2026. More striking is that it embraces companies ahead of their IPOs—recently including SpaceX SPCX, Cerebras Systems CBRS, and Anthropic.
That access is where the two funds part ways. JPMorgan Large Cap Growth owns many of the same off-benchmark names, but it holds no private companies. It waited for Cerebras to go public in its mid-2026 IPO before buying, at least eight months after Fidelity already owned it. Both managers like many of the same ideas, but only one had the leash to act on them early. Active share sees none of it: It counts a stake bought the week of an IPO the same as one bought years earlier in a private round, and still tags the fund that waited as the bolder of the two.
Active Score catches what active share missed: Fidelity Blue Chip Growth scores 66, while JPMorgan Large Cap Growth scores 49—the ranking active share had backward.
Active Score vs. Off-Benchmark and Private Exposure, Fund by Fund
A House-Style Signal
The vertical spread on that scatter clusters by firm, not by individual fund, and points to house culture.
Roll the dimensions together, and the firms fall into a clear order. Fidelity’s large-cap funds carry the highest average Active Score of the four, around 71. MFS and J.P. Morgan sit in the middle, near 65 and 56, respectively. T. Rowe Price anchors the bottom, around 53.
Private companies are a sharp dividing line behind those scores. Nineteen of Fidelity’s 28 large-cap funds hold a stake in a private business, as do six of T. Rowe Price’s nine. At JPMorgan, one fund in seven does; at MFS, none do. The stakes stay small, averaging 1.7% of assets among the Fidelity funds that hold them and 1.4% at T. Rowe Price, though Fidelity Advisor New Insights FINSX has typically carried about 5% and T. Rowe Price Large-Cap Growth TRGOX roughly 4%. (Morningstar Direct users can check any portfolio through the Private Allocation Percent data point.)
Who Ventures Private?
Look at private holdings alone, though, and MFS would seem the most benchmark-bound of the four. Its funds own no private companies—yet MFS Massachusetts Investors Growth Stock MIGFX keeps nearly 38% of assets outside its benchmark, lifting it to an Active Score of 102, the highest fund reading in the sample, surpassing even Fidelity’s most adventurous fund at 100.
T. Rowe Price is the mirror image. Its funds buy private companies nearly as often as Fidelity’s while carrying the lowest average off-benchmark weight of the four. A firm can indulge one kind of freedom, roaming among public stocks or reaching into private ones, while shunning the other. A single score is what catches both.
When A Manager Leaves
How far a fund wanders changes the stakes when its manager departs. A manager change deserves a hard look at whichever fund it hits; differences in how a manager weights even the same roster of stocks can have profound effects, which is why Morningstar’s analysts weigh every such change carefully. But a departure raises an extra question at a fund that roams widely. A successor might reweight familiar index names differently. They might treat a sleeve of off-benchmark and private positions—often built through the outgoing manager’s own network and judgment—differently. That’s one more variable to weigh before any conclusion. Scale and access can outlast any single manager, too: A big firm’s pipeline to private deals doesn’t leave when a name on the door does.
The Other Side of a Long Leash
Room to buy outside the benchmark is also room to own a great stock before the index admits it. That was the advantage for Fidelity Blue Chip Growth and other large-growth funds holding memory and chip stocks through 2025 and 2026, while those names were still classified as value and their benchmark-bound competitors waited for the index to be redrawn. The freedom that makes a fund harder to pin down is the same freedom that lets it get somewhere first.
So, Whose Leash Is Longest?
Among these four big shops, Fidelity’s funds hold the most outside their benchmarks and reach into private companies most often—and carry the highest Active Scores to match. The four can still share a similar active share figure, but each has made different choices about exactly how their portfolio managers may derive it.
If the distinction shows up here, on the industry’s most well-trampled ground, it matters more in wilder territory. Investors in interval funds, tender-offer funds, and the other increasingly popular semiliquid structures that blur the line between public and private assets may have the most to gain from a measure that looks past a single number to where a fund actually invests.
Special thanks to Don Phillips, whose original idea inspired this research.
The author or authors do not own shares in any securities mentioned in this article. Find out about Morningstar’s editorial policies.
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