Two things happened to the companies that make the physical plumbing of an artificial-intelligence rack — the high-speed backplane connectors, copper cable assemblies, busbars and power-shelf interconnect that move 800-gigabit signals and hundreds of amps between graphics processors — in the last three weeks of July. Their order books hit records. Their shares fell.

Amphenol: the business and the tape agree

Amphenol, which makes electrical, fibre-optic and radio-frequency connectors, busbars and custom cable assemblies for equipment makers and contract manufacturers, reported June-quarter sales of $8.76bn, up 55% year on year and up 30% organically. Its information-technology and datacom business — 43% of sales — grew 89%, of which 63% was organic, and management said AI-related revenue now runs at an annual rate of $10.5bn to $11bn. Gross margin widened 417 basis points to 40.5%; operating income grew 81% on 55% more revenue. Orders of $10.7bn were up 94%, a book-to-bill of 1.23x, with organic order growth of 63%. The $10.5bn CommScope connectivity acquisition is contributing — guidance was raised to $4.6bn of sales and $0.30 of earnings accretion from $4.1bn and $0.15 — but it is not the source of the growth.

Not everything is growing: communications networks fell 6% organically and management guided that line to a mid-teens sequential decline.

Verdict on the business: CONFIRMS. On valuation: the shares trade at 39.9x trailing and 31.8x forward earnings, 18.5x trailing gross profit against 21.2x in early May. The price is up about 20% since 4 May while the trailing multiple compressed 13% — earnings outran price. The check on that is consensus, which has revenue growth falling from 54% this year to 17.7% next, putting the stock near 26x fiscal 2027 earnings of $6.43. The average of 17 analyst price targets sits at $198.

TE Connectivity: the dislocation

TE Connectivity, an Ireland-based maker of connectors, sensors, relays and cable assemblies split between transportation and industrial customers, is the same trade at half the multiple and none of the applause. Fiscal third-quarter revenue was $5.16bn, up 13.8%. Orders were a record $5.7bn, up 27%, a 1.1x book-to-bill on a record backlog, with industrial orders up 36% and digital data network orders up 70% — enough for management to claim "heightened confidence" in fiscal 2027. Digital data network sales grew 34% organically, AI is now the majority of that segment, and the $3bn AI-cloud revenue target set for fiscal 2027 has already been reached. The energy business grew 33% organically, a fifth of it directly from data-centre build-outs.

The shares fell about 7% on the print despite beats on revenue and earnings, with the market treating fourth-quarter guidance as merely in line and the $1.4bn Astrodyne TDI power-supply acquisition as a use of cash. The stock's 50-day average has sat below its 200-day since 18 May.

Business: CONFIRMS. Tape: CONTRADICTS. TE trades at 20.8x trailing and 18.7x forward earnings, 14.5x trailing enterprise value to EBITDA and a 5.9% trailing free-cash-flow yield — multiples essentially identical to early May, against company guidance of roughly 15% revenue and more than 20% earnings growth this fiscal year and consensus of $12.96 a share next.

The small caps carried the year, and cost the most

Bel Fuse, which makes fuses, magnetics, power converters and connectors for data infrastructure and defence, grew revenue 25.2% to $210.7m with data solutions up 55% to $58m on a high-performance-computing ramp, gross margin up 118 basis points to 39.9%, and a positive book-to-bill for six straight quarters. Business: CONFIRMS. Valuation: stretched — 29.9x forward earnings and 24.4x trailing EV/EBITDA against consensus revenue growth of just 8.0% next year, with the diluted share count up 8.4% after May's equity raise.

CTS, which makes sensors and actuators mostly for vehicles, is not really in this story: revenue grew 6.6%, transportation fell 2%, aerospace and defence fell 15%, and it discloses no data-centre revenue. It did post a record 41.5% adjusted gross margin and $163m of new transportation awards. INCONCLUSIVE, on a 23.75x forward multiple built from a single analyst's estimates. It is diverging from its peers, not following them.

Copper, and the 800-volt caveat

London copper touched $14,258 a tonne and New York futures $6.77 a pound on 7 August, a record, as US stockpiles swelled ahead of a tariff decision. All four companies still widened gross margin year on year — the clearest evidence against the view that this is a commoditising step of the chain.

The content story cuts both ways. NVIDIA is moving racks to 800-volt direct-current distribution from 2027, and that transition removes roughly 200kg of copper busbar per megawatt rack rather than adding it; the connector opportunity is high-voltage qualification and touch safety, not copper mass. On the rival risk — optics replacing copper — TE's management said copper remains the "workhorse" inside the rack, with optical links material only from 2028, and is demonstrating 224-gigabit-per-lane copper cable assemblies today.

One last caution on the tape: roughly a third to half of the past month's gain landed in the single 4 August session — Bel Fuse +9.4%, TE +5.8%, Amphenol +4.9% — the day the S&P 500 set a new intraday high after the Nasdaq's worst month since March. That was an AI-hardware repricing, not a connector event.

The setup

Where it stands — Record order books at Amphenol and TE Connectivity, with only Amphenol's shares reflecting them. Would confirm — TE's fourth-quarter digital data network organic growth holding above 30% with book-to-bill above 1.0x. Would invalidate — Amphenol's IT datacom organic growth falling below 20%, or book-to-bill dropping under 1.0x. Watch next — TE Connectivity's fiscal fourth-quarter results in late October, with first fiscal 2027 guidance. Valuation — Amphenol 39.9x trailing, 31.8x forward versus ~34x forward in May; TE 20.8x trailing, 18.7x forward, unchanged since May.