Energy and Metals Rally While Major Indices Slip; Amphenol Sinks 47.5%

2026-09-05 · Money Checkup market briefing

Stocks mostly drifted lower this week even as small caps eked out a gain. The Russell 2000 was the lone major index in positive territory at 2975.65 (+0.25%), while the S&P 500 (7718.6, -0.38%), Dow Jones (53414.25, -0.51%), and Nasdaq Composite (26506.99, -0.29%) all pulled back. It wasn't a dramatic week at the index level, but underneath the surface there was a lot of movement — including one of the more eye-catching single-stock drops we've seen: Amphenol Corp (APH) fell 47.5%.

On the gainer side, System1 (SST) more than doubled, up 102.6%, while Titan Machinery (TITN) jumped 46.8%. A handful of biotech and biotech-adjacent names also had strong weeks, with Summit Therapeutics (SMMT) up 28.2%, Opus Genetics (IRD) up 26.6%, and Tarsus Pharmaceuticals (TARS) up 26.5%. CarParts.com (PRTS) rose 27.9%, and both IREN Ltd (IREN) and Montauk Renewables (MNTK) climbed 26.0%.

The losers list was headlined by that Amphenol slide, but it wasn't alone: Ultragenyx Pharmaceutical (RARE) dropped 40.3%, Tron Inc. (TRON) fell 28.8%, and Datavault AI (DVLT) lost 27.1%. Credo Technology Group (CRDO) declined 26.7%, and Enovis Corp (ENOV) was down 25.5% to round out a rough week for several names across very different corners of the market — semiconductors, healthcare, and industrials all took hits.

Sector rotation was one of the clearer stories this week. Commodity-linked industries led the pack by a wide margin: Coal Mining stocks averaged a 27.1% gain across five companies, including Warrior Met Coal, Core Natural Resources, and Peabody Energy. Integrated Oil Companies weren't far behind at +24.1% across eight names like Chevron, ConocoPhillips, and Marathon Petroleum, and Precious Metals gained 17.4% across seven companies including Newmont and Royal Gold. Auto & Home Supply Stores also had a strong week, up 15.3%, led by names like O'Reilly Automotive and AutoZone.

On the weak side, Blank Check companies fell 22.4% on average (albeit across just three names), and Multi-Sector Companies dropped 18.9%, with InterDigital and Digital Turbine among the names dragging that group down. Transportation-related industries had a tough week too: Air Freight/Delivery Services fell 15.4% across eleven companies including FedEx, Delta, and United Airlines, while Water/Sewer/Pipeline & Power Line Construction stocks also declined 15.4% across six names like MasTec and Dycom Industries. Wholesale Distributors rounded out the weak list, down 14.0%.

On the filings front, several companies posted new annual reports this week. Ethan Allen Interiors (ETD) filed its FY2026 10-K with a Health Score of 78.1, the strongest of the batch. Jack Henry & Associates (JKHY) filed with a score of 58.8, Strattec Security (STRT) came in at 65.6, and Alpha & Omega Semiconductor (AOSL) posted a 53.3. Matrix Service (MTRX) filed with a notably lower Health Score of 41.0, and Hyperliquid Strategies (PURR) landed at 52.3.

Separately, five companies remain flagged with going-concern audit notes, meaning auditors have expressed substantial doubt about their ability to continue operating without additional capital or a change in circumstances: Entrada Therapeutics (TRDA), FS KKR Capital Corp (FSK), Bain Capital Specialty Finance (BCSF), New Mountain Finance Corp (NMFC), and Innovative Industrial Properties (IIPR).

For readers tracking this week's action, Money Checkup's Health Score can be a useful lens on names like Matrix Service or Hyperliquid Strategies that just filed fresh financials — comparing their scores against peers in the same industry may add context beyond the headline price moves.

Not investment advice. Data and analysis only.