XBI Ignored The Market’s Downturn

Your biotech fund just posted a big gain, but the reason why is more about the whole sector than any single star.

Twist Bioscience (TWST), at just 2.0% of the fund, rose 55.6% last month, helping to lead a rally that saw the State Street SPDR S&P Biotech ETF (XBI) climb +15.6%. That move is notable because it happened while the broader S&P 500 (SPY) actually fell -2.9% over the same period.

When an exchange-traded fund moves that differently from the market, you want to know if you’re riding a broad wave or just the fortunes of one or two companies. Looking under the hood of XBI gives us the answer.

So Who Else Powered The Climb?

While Twist Bioscience was the single biggest driver, it had plenty of company. Another holding, uniQure (QURE), made up just 1.1% of the fund but rose 88.8%, adding about 0.9% to the fund’s total move. Close behind was Apogee Therapeutics (APGE), which, at 1.3% of the fund, rose 70.5% and also added about 0.9% to the fund’s return.

Together, these three stocks were responsible for about 23% of the fund’s entire gain. That’s a meaningful contribution, but it doesn’t tell the whole story.

A Sector-Wide Lift, Not A Few Stars

The real story here is breadth. Among the fund’s 50 largest holdings, an overwhelming 44 rose while only 6 fell over the past month. This wasn’t a case of a few winners carrying a basket of losers. The positive performance was spread widely across the portfolio.

This is consistent with how XBI is built. The fund holds 157 positions and tracks a modified equal-weighted index, a structure designed to ensure balanced representation and avoid having a few giants dictate the fund’s direction. The recent performance shows that design in action: the move came from across the biotech industry, not from a concentrated position in a few names.

What This Means For Your Position In XBI

If you hold this fund, you just saw a clear example of what you own: a proxy for the biotechnology segment of the market. The fund’s recent gain was a sector story, not a stock-picking story. Your investment rose because sentiment lifted the overwhelming majority of the basket, allowing it to diverge sharply from the broader market.

The takeaway is that your exposure is to the collective health of the biotech industry. The fund is doing its job of delivering the sector’s return, which means its performance will be tied to the specific dynamics of that industry, for better or worse.

So Where Does That Leave You?

So this was mostly the market moving through XBI, not any one holding. Knowing what moved the fund is the start; the useful question is what it means for the money you have in it.

A single stretch of performance is only half the picture. It tells you what just happened, not whether the fund is reasonably valued today or how it compares with its peers on return and risk. Before you add or trim on the back of a move like this, it is worth seeing where it actually stands: our ETF Valuation and Performance Scorecard lines the major ETFs up side by side, so a move becomes one input rather than the whole decision.

Exposure You Chose, Or Inherited?

There is also a deeper point this move exposes. An index fund hands you whatever it weights most, so when a few names can swing the whole fund, you may be carrying a concentration you never chose. The move simply made it visible.

If you would rather your exposure be deliberate, our High Quality (HQ) Portfolio is built on a different idea: rule-based, multi-factor selection across different kinds of businesses, re-balanced on a schedule, so no two or three names quietly come to decide how your money does. It has a record of outpacing a benchmark that combines the three major indices – the S&P 500, S&P Mid-cap, and Russell 2000.