Best Biotech ETFs

Almost every meaningful difference between biotech ETFs flows from how they weight their holdings. Market-cap-weighted funds give the biggest companies the biggest share, so the fund leans on large, established, profitable biotechs. Equal-weighted funds give every holding roughly the same slice, so small and even pre-revenue companies carry as much weight as the giants. That single design decision drives the risk, the return pattern, and how the fund behaves through a biotech cycle.

In practice it means a market-cap fund like IBB is anchored by a handful of mega-cap names, while an equal-weight fund like XBI is spread thin across roughly 130 stocks where a tiny clinical-stage biotech matters about as much as Amgen. Equal-weight tends to outrun cap-weight when small biotech is in favor and fall harder when it is not. Neither is better; they are different exposures to the same sector.

IBB (iShares Biotechnology ETF) is the benchmark biotech fund. It tracks the Nasdaq Biotechnology Index with a market-cap-weighted approach, so it tilts toward large, established biotechs like Amgen, Gilead, Vertex, and Regeneron, and its top ten holdings can be close to half the fund. That concentration in profitable companies gives IBB more large-cap stability than an equal-weight fund, at an expense ratio of around 0.44% to 0.45%. It is the more conservative way to own biotech.

BBH (VanEck Biotech ETF) is also market-cap weighted but far more concentrated, tracking roughly the 25 largest and most liquid US-listed biotechs. That skews it toward blue-chip names like Amgen, Gilead, Vertex, and Regeneron even more heavily than IBB, at a lower fee of around 0.35%. The trade-off is diversification: with so few holdings, BBH lives and dies by its biggest positions, where IBB spreads across a wider list.

XBI (SPDR S&P Biotech ETF) is the most popular equal-weight option and the structural opposite of IBB. It spreads roughly equal weight across about 130 biotech stocks, which means small and clinical-stage companies carry meaningful weight rather than being rounding errors. That gives XBI a higher-risk, higher-reward profile: it is far more sensitive to small-cap catalysts like trial readouts and FDA decisions, tends to outperform in biotech bull markets, and falls harder in downturns. Its expense ratio is around 0.35%.

FBT (First Trust NYSE Arca Biotechnology Index Fund) takes a similar small-cap-friendly approach with a modified equal-weight method, holding a smaller, more curated basket of names at a higher fee of around 0.56%. Both XBI and FBT lean toward the more speculative end of biotech, so they swing more than the cap-weighted funds. This is descriptive, not a recommendation to buy any particular fund.

ARKG (ARK Genomic Revolution ETF) is a different animal again. It is actively managed by ARK Invest and concentrates on genomics, gene editing, and precision-medicine innovation rather than tracking a broad biotech index. It tends to hold smaller, earlier-stage, and more speculative companies, and at an expense ratio of around 0.75% it is the priciest of the funds here because someone is actively picking the holdings.

That makes ARKG a focused thematic bet on a specific corner of biotech, not a diversified way to own the industry. It has been highly volatile, with large swings in both directions, and its returns can diverge sharply from the broad biotech indexes. It suits investors who specifically want concentrated genomics exposure and understand the risk, rather than anyone looking for steady, diversified biotech.

Biotech is one of the most event-driven corners of the market. A single company can rise or fall sharply on one binary outcome: a clinical-trial readout, an FDA approval or rejection, a patent ruling, or a buyout. Smaller, pre-revenue biotechs can move 50% or more in a day on trial news, because their entire value rests on drugs that have not yet proven they work. Equal-weight funds like XBI feel this most, since small names carry real weight; cap-weight funds like IBB are cushioned by large, profitable companies with approved products.

This is also why biotech is not the same as healthcare. A broad healthcare ETF such as XLV (Health Care Select Sector SPDR) holds pharma, insurers, device makers, and services alongside some biotech, which makes it far more diversified and much less volatile. Pure biotech funds concentrate on drug developers, so they swing harder in both directions. If you want the whole sector rather than its most volatile slice, healthcare and biotech are genuinely different decisions.

Costs are approximate expense ratios as of early 2026; verify the current figure on each issuer's site. IBB and BBH are market-cap weighted and lean toward large, profitable biotechs, with BBH the more concentrated of the two. XBI and FBT use equal-weight methods that give small and clinical-stage names more say, which makes them more volatile. ARKG is an active genomics bet at a higher fee. For how biotech sits among other sector options, see our best ETF in every category guide.

The hard part of biotech is not finding a fund; it is deciding whether biotech belongs in your portfolio at all, how large a slice makes sense given how much it swings, and whether you want the steadier large-cap tilt (IBB, BBH) or the riskier small-cap tilt (XBI, FBT). Those questions depend on what you already own, how much volatility you can sit through, and whether you already hold biotech inside a broad healthcare or total-market fund, which is where an AI assistant that can reason over your real holdings is useful.

That is where Walnut fits. It connects your existing brokerage through SnapTrade so you can ask, in plain language through Claude, ChatGPT, or a built-in assistant, how a biotech ETF would fit what you already hold, how much a volatile position like XBI would move the rest of your portfolio, and how cap-weight and equal-weight funds are doing against the market. Walnut keeps your accounts read-only, so a biotech position is only ever added when you place that order. As something that informs rather than advises, it sizes the question of a biotech sleeve against your real holdings instead of recommending one, because Walnut is not an investment adviser.

Biotech ETFs come down to one structural choice. Market-cap-weighted funds, IBB (the broad benchmark) and BBH (a concentrated large-cap version), lean on large, profitable biotechs and are the steadier way in. Equal-weight funds, XBI (the popular choice) and FBT, give small and clinical-stage names real weight, which makes them more volatile and more sensitive to trial results. ARKG is an active, higher-fee bet on genomics innovation, not a diversified core holding.

Whichever route, the honest framing is the same: biotech is binary and event-driven, so it swings far more than the broad market and is usually sized as a small satellite position rather than a core one. Note too that pure biotech is not the same as broad healthcare. From a connected account you can dig into any of these as an ETF, or compare a biotech fund against the rest of your portfolio. Holdings, fees, and index methods change; treat the specifics here as a starting point and confirm on each provider's site before deciding. For the full category map, see our best ETF in every category guide.