THNR's rebalance moved the trade to the trial money

Amplify's weight-loss ETF rebuilt its holdings on Sept. 18, and the VettaFi Weight Loss Drug & Treatment Index behind it changed which companies carry the trade: Gilead Sciences and Structure Therapeutics entered the 20-stock benchmark, while Scholar Rock Holding and Hims & Hers Health came out, as ETF Trends first reported.

Hims & Hers had lost nearly half its value over the same stretch before the index cut it loose, while the index's two largest contributors were established drugmakers — Merck, ahead 42.4% year to date, and Innovent Biologics, ahead 25.7%, according to VettaFi. The replacements fit that pattern: Structure Therapeutics enters under the index's Phase 3 Drugs category, and Gilead, whose weight-loss pipeline the ETF Trends account does not describe, reached 5.2% of the fund within days of its debut. In a 20-stock book, a new name arrives at full size rather than growing into one.

Eli Lilly, the fund's top holding at nearly 10% of assets, grew second-quarter revenue 48% to $22.97 billion on Mounjaro and Zepbound demand, raised its 2026 revenue forecast to $85 billion to $87 billion, and has Retatrutide queued for an FDA filing in early 2027, per TradingView. AstraZeneca, at a 5.4% index weight, moved its oral weight-loss pill elecoglipron into Phase III trials in June after a mid-stage result of 11.8% weight loss at 36 weeks on the highest dose against 0.3% for placebo. Roche, the index's fourth-largest holding at 5.3%, agreed in August to pay Hanmi Pharmaceutical $190 million upfront and as much as $2.3 billion for a muscle-sparing weight-loss drug, BioPharma Dive reported. Oral dosing, longer intervals and muscle preservation are the lanes the trial money is funding, in a market Morgan Stanley expects to reach $150 billion by 2035 from $15 billion in 2024, a projection Amplify cites on its website.

The return, though, still comes from the largest names in the book: established drugmakers drove most of the index's gains before the reshuffle, so the payoff is concentrated in the mega-caps while the differentiation rests on Structure Therapeutics and the other trial-stage names that have not paid yet. That is a hard pitch at any asset level, and it is the one the index's rules have now doubled down on.

The number the rebalance cannot touch is the fund's size: THNR held about $5.8 million in net assets as of Sept. 18, and net asset value gained 5.9% year to date through August against 6.5% for the index over the same stretch. A 0.6-point lag is the shape of the wrapper's cost, which is the correct result for a fund built to track, and it leaves asset growth — not index construction — as the variable that decides whether the trial-stage bets ever get a real balance sheet behind them. Thematic funds have been selling labels for years, as this publication has argued, and this one has a label carrying more weight than its asset base does.

The catalyst is already dated: Lilly plans to file Retatrutide with the FDA in early 2027, when the index's two halves — the mega-cap that carries the return and the Phase 3 names that might — will be judged together. If oral and muscle-sparing data keep landing the way elecoglipron's did, the index will look early; if Lilly keeps driving the return, the fund will look like a cost-bearing route to its own top holding.