Seven semiconductor companies that supply the timing, radio-frequency and optical components used to move signals inside and between artificial-intelligence datacenter racks reported earnings over the past two weeks, and the results split the group in two: four posted genuine beat-and-raise quarters tied to datacenter demand, while two of the seven diverged for reasons that have nothing to do with datacenters. That matters because a simple twelve-month average return for the group — roughly +187% — hides that the gain was carried almost entirely by four names, and the past month's average pullback of about 4% conceals a spread from +12% to -22% across members.

This is a story split by business model, not a uniform sector move. SiTime (SITM), which makes silicon oscillators and clock chips that synchronize signals inside servers and networking gear, jumped 26.6% on August 6 after second-quarter revenue of $157.4 million, up 127% year over year, with non-GAAP gross margin rising 890 basis points to 67.1%. Its communications-and-datacenter segment grew 181% year over year to $101 million — a ninth straight quarter of triple-digit growth, on clock adoption inside 1.6-terabit optical modules — and third-quarter guidance of $285-295 million came in well above the $219.7 million Wall Street expected. CONFIRMS: the pop tracks disclosed, dated numbers.

MACOM (MTSI), which designs radio-frequency-to-optical chips for telecom, defense and datacenter networking equipment, rose 14.5% the same day, extending a rally begun by its own August 4 report — revenue of $342.2 million (+35.8% year over year), gross margin of 58.3%, and operating income more than doubling to $77.1 million. CONFIRMS on the business, but forward earnings multiples near 60x are well above the roughly 30x level this desk's own prior research flagged as already pricing an optimistic optical-networking ramp.

MaxLinear (MXL), which makes RF and mixed-signal chips for broadband and optical datacenter links, returned to GAAP profitability in its July 23 report, with revenue up 55% to $168.8 million and its now-largest infrastructure segment up 145% to about $85 million on datacenter demand; management raised its 2026 optical-datacenter revenue guide to $210-230 million. Yet the stock is down 18.4% over the trailing month even as it remains up 362% over the past year — the business accelerated while the shares digested a year of gains, a positive divergence rather than a warning sign.

Applied Optoelectronics (AAOI), which manufactures the optical transceivers and lasers that carry data between servers, posted revenue of $191.9 million (+86% year over year), returned to non-GAAP profitability, and raised its full-year guide to more than $1.1 billion from $455.7 million in 2025, backed by a disclosed hyperscaler order for more than $200 million of 1.6-terabit transceivers and a follow-on $53 million 800-gigabit order. But gross margin has compressed for three straight quarters, from 31.2% to 27.7%, the company remains loss-making at the operating line, and diluted share count is up 44% year over year. Shares fell 3.4% the day after the beat, but the stock's current downtrend reading largely reflects a June-July collapse from $171 to $76 that preceded the print. Industry data support the demand side of the story: 800-gigabit shipments are set to more than double in 2026 as 1.6-terabit modules enter volume production, arguing against a broader hyperscaler order pushout. MIXED: demand confirms, margin and dilution do not.

Semtech (SMTC), which makes analog chips including optical signal-integrity components for datacenters, rose 11.2% alongside the group, but its own next earnings report isn't due until August 25 — this move is sympathy with SiTime and MACOM, not confirmed by fresh Semtech numbers. INCONCLUSIVE.

Qualcomm (QCOM), the mobile-chip and patent-licensing giant that also sells automotive and datacenter processors, fell 14% over the past month after disclosing that Apple's iPhone-modem share for the coming launch is running well below the roughly 20% previously assumed, implying a roughly 50% sequential drop in handset revenue into the December quarter. Automotive revenue hit a record $1.6 billion (+61%), and management raised its 2029 non-handset target to $40 billion, including $15 billion of new datacenter custom-silicon business — years out. CONTRADICTS the datacenter-AI framing: Qualcomm's near-term move is a handset story, not a chip-demand one, and at 15.1x forward earnings and 3.9x forward sales it is priced almost entirely for that risk.

indie Semiconductor (INDI), which supplies chips and software for automotive driver-assistance and connectivity systems, posted essentially flat revenue near $217 million versus a year ago with a negative gross-margin quarter, and fell 21.5% over the trailing month, the worst in the group. CONTRADICTS.

On the dashboard's daily trend measure, Applied Optoelectronics and indie Semiconductor both flipped from a mild uptrend to a mild downtrend in early August, while SiTime, MACOM, MaxLinear, Qualcomm and Semtech remain in a mild uptrend after stepping down one notch from a strong uptrend in July. None of the seven appears among the market's most extreme movers over the past month — this reads as rotation among names with different stories, not a sector-wide break.

The setup

Where it stands — Four datacenter-facing suppliers (SITM, MTSI, MXL, AAOI) beat and raised; QCOM and INDI diverge on unrelated handset and auto-chip weakness. Would confirm — Semtech's August 25 report shows datacenter/optical revenue growth and gross-margin expansion in line with SiTime and MACOM. Would invalidate — AAOI's gross margin resumes its decline below 27% next quarter, or MaxLinear's optical-datacenter revenue guide is missed. Watch next — Semtech's fiscal Q2 earnings report, scheduled for August 25, 2026. Valuation — MACOM trades at 60x forward earnings versus its own ~30x prior anchor; Qualcomm at 15.1x forward earnings, cheapest in the group.