Shares in US expertise giants have risen so quickly this yr, pushed by a synthetic intelligence frenzy, that their index weighting has skewed Wall Road’s general efficiency — and prompted traders to run remarkably related portfolios.
Alphabet, Amazon, Apple, Meta, Microsoft, Nvidia and Tesla — that are among the many greatest 10 firms on the S&P 500 — have accounted for about half the bellwether index’s positive factors within the yr to October.
This affect implies that lively fund correlation, a measure of how equally funds carry out, has tightened significantly.
This present scenario mirrors that with the 5 greatest power teams within the aftermath of Russia’s invasion of Ukraine in 2022. Again then, Chevron, ExxonMobil, BP, Shell, and TotalEnergies all outperformed because of the warfare, amassing complete earnings of almost $200bn within the yr. Fund managers with little publicity to grease majors on the time have been caught within the crosshairs as their boards and traders demanded causes for his or her underperformance.
James Thomson, who manages the equity-based World Alternatives Fund at Rathbones Group, one of many largest listed wealth managers within the UK, says the difficulty with tech-stock correlation is a “supply of tension”.
“It’s a battle for lively funds to outperform in a concentrated market, the place the returns are coming from a small variety of shares with a excessive index weighting,” he says.
Within the US, at present, the highest 10 shares of the S&P 500 index make up greater than 35 per cent of your entire benchmark — essentially the most concentrated weighting in at the least 40 years, in accordance with Financial institution of America analysis. And the affect of the seven massive tech shares was laid naked within the first quarter of 2024 when the index fell 5 per cent with out them however, together with them, gained 7.6 per cent, in accordance with JPMorgan knowledge.
Globally, on the finish of June, the seven accounted for 12 per cent of the market worth of the MSCI World Index, which incorporates about 1,397 shares in complete.

This implies many actively-managed international fairness funds are behaving like index trackers. Supposedly various managed portfolios and discretionary managed funds are behaving equally, with little to distinguish themselves from each other.
In consequence, extra traders are actually uncovered to the hazard of a correction, which might hit all of the portfolios uncovered to the highest 10 shares notably onerous. “They’re marching ever-higher up the steps,” Thomson says. “However, if there’s an air pocket or perhaps a normalisation, they’ll take the elevator straight down.”
For traders, such shut correlation between lively funds means a stability needs to be struck between performance-chasing and bottom-racing. Shunning the outperformers will harm within the brief time period however investing on the unsuitable time will deliver long-term underperformance.
Given these dangers, why are so many lively funds behaving on this copycat vogue? In line with Joe Wiggins, funding analysis director for St James’s Place, the more and more concentrated nature of inventory markets is giving them much less flexibility.
Globally, new listings have dwindled for the reason that pandemic, whereas merger and acquisition exercise has helped to shrink fairness markets whereas, on the similar time, creating company giants. This will increase index focus, and offers lively fund managers fewer alternatives to create portfolios which can be considerably completely different to passive (or tracker) funds.
On high of that, there’s the “zeitgeist” impact, whereby sure narratives change the general market dynamic — comparable to the present obsession with synthetic intelligence. More cash is piled into these shares, boosting their market capitalisation and growing sector focus.
“It may be onerous to be a contrarian when slender sectors and themes are main the market,” says Wiggins. “Whether or not they’re doing it intentionally, or it’s an unconscious behavioural bias, extra managers are investing within the [seven big tech] shares.”
Conflicts of curiosity may also come into play. When a fund’s traders and its board demand quarter-to-quarter development, and the fund supervisor’s pay is at stake, it may be tough to not chase successful shares and, as a substitute, take a contrarian view.
Dan Brocklebank, head of UK at Orbis Funding, warns that “this ripples by means of to the portfolio administration and this affect could be very highly effective”, leading to extra correlation between funds.
Communication is essential, Brocklebank says. When he explains to traders why Orbis goals to maintain fund correlations low, they’re ready to remain the course.
“There’s a hazard in creating perverse incentives that imply lively managers don’t steer away from what different persons are doing,” says Wiggins.
How, then, can lively managers ensure that they’re diversified sufficient to keep away from a correlation downside?
Chris Mellor, head of Emea ETF fairness product administration at Invesco, advocates for an equal-weight method — protecting all holdings on the similar share inside a portfolio — as a method of navigating focus and correlation bias.
This may mitigate the dangers that prime correlation brings, whereas nonetheless gaining from a small publicity to market favourites — resulting in good long-term efficiency.
Alternatively, “top-slicing” the earnings from the largest seven tech shares, and reinvesting them into different fairness alternatives, can keep away from the focus downside.
For Brocklebank, company buildings and incentives should even be addressed, permitting managers to have conviction of their holdings. Solely then can lively managers be actually lively.