---
title: "MACOM sells the optical front end OCP says suppliers still lack, and CoreWeave credit fear cut the stock 20%"
description: "MACOM put a complete 3.2T optical front end on sale in September and called every part readily available, while research from the OCP summit published this morning lists 400G-per-lane TIAs and drivers as unavailable from suppliers. A week of CoreWeave credit fear cut the stock by a fifth anyway; the fiscal Q4 report, estimated for November 5, decides which camp is right."
publisher: "The Inference"
section: "Hardware"
published: 2026-10-21T14:12:49.381Z
modified: 2026-10-21T14:12:49.381Z
canonical: https://theinference.org/article/macom-sells-the-optical-front-end-ocp-says-suppliers-still-lack-and-coreweave-credit-fear-cut-the-stock-20
language: en
keywords: "Semiconductors, Optical Networking, Stocks, Earnings, Insider Selling"
---

# MACOM sells the optical front end OCP says suppliers still lack, and CoreWeave credit fear cut the stock 20%

> MACOM put a complete 3.2T optical front end on sale in September and called every part readily available, while research from the OCP summit published this morning lists 400G-per-lane TIAs and drivers as unavailable from suppliers. A week of CoreWeave credit fear cut the stock by a fifth anyway; the fiscal Q4 report, estimated for November 5, decides which camp is right.

## The shortage MACOM says it already fills

On September 17, MACOM, a Lowell, Massachusetts semiconductor supplier, announced a front-end chipset for 3.2T optical links: eight channels at 448 Gbps PAM-4, the modulation behind next-generation AI data center interconnects [1]. The set pairs new quad transimpedance amplifiers, the receive chips that turn a photodiode's current into voltage, with a photodiode rated above 100 GHz of bandwidth and transmit drivers introduced earlier, and [the release called every product "readily available"](https://www.streetinsider.com/Globe+Newswire/MACOM+Introduces+3.2T+Chipset+Solution+for+High+Speed+Optical+Connectivity/27073085.html) [1].

[Research published this morning from the Open Compute Project summit](https://fundaai.substack.com/p/researchoptics-ocp-2026-points-to), the hyperscaler hardware conference held in San Jose from October 12 to 15, met [MACOM](https://theinference.org/markets/companies/macom-technology-solutions) among more than twenty optical-interconnect companies and still recorded the front end as the bottleneck: DSPs, TIAs and drivers for 400G per lane "are not yet available from suppliers" [2].

## A 41 percent step, guided before the rout

The September quarter was MACOM's strongest: revenue of $342.2 million, up 35.8 percent year over year and 18.4 percent sequentially, adjusted EPS of $1.40 against a $1.35 consensus [3][4]. [The fiscal fourth quarter guide, issued August 6](https://www.sec.gov/Archives/edgar/data/1493594/000149359426000036/ex99_1earningsreleaseq3fy26.htm), calls for revenue of $415 to 425 million, up to 16 percent above the Street's $365.86 million, and adjusted EPS of $1.97 to 2.03, a 41 to 45 percent step above the September quarter in one print [3][4].

*Chart: **Eleven straight quarterly increases, and the fastest annual growth since early 2025** Line chart of MACOM quarterly revenue rising from about $150 million in late 2023 to $342.2 million in the July 2026 quarter*

*Quarterly revenue, US$ millions, calendar-quarter labels (MACOM's fiscal Q3 2026 ended July 3, 2026). Source: MACOM's SEC filings, retrieved October 21, 2026. [5]*

## Someone else's credit took a fifth of the value

In the week to October 16, none of that was company news [5]. The stock opened Monday at $324.20, touched $257.12 Thursday and closed Friday at $262.24, down 20.55 percent while the S&P 500 slipped 1.95 percent [5].

The sector did the selling: [the Philadelphia Semiconductor Index fell more than 12 percent in eight sessions](https://longbridge.com/en/news/302173332) toward its longest losing streak since 2006, shorts booked roughly $32 billion of paper profits in seven days, and credit-default swaps on [CoreWeave](https://theinference.org/markets/companies/coreweave), an AI cloud computing firm, implied better-than-even odds of default inside five years [6]. The same tape cut [Ciena](https://theinference.org/markets/companies/ciena), [Coherent](https://theinference.org/markets/companies/coherent) and Applied Optoelectronics by about a quarter, with [four Ciena officers selling $2.6 million of stock](https://theinference.org/article/ciena-promised-30-growth-through-2029-four-executives-sold-2-6-million-of-stock-mid-slide) [7].

## The insiders sold at $326 and $300

MACOM's insiders sold from higher ground. Chief financial officer [John Kober](https://theinference.org/markets/people/john-kober) sold 7,389 shares for $2.41 million at an average $326.08 on August 17, 18 percent of his direct holding, under a preset 10b5-1 trading plan; senior vice president Ambra Roth sold 653 shares at $300.00 on October 1; ninety-day insider sales total 8,294 shares for $2.67 million [8].

[A Form 144 notice of a proposed insider sale, dated October 18](https://uk.investing.com/news/stock-market-news/form-144-macom-technology-solutions-holdings-for-18-october-93CH-4916446), surfaced on October 19 with no amount attached, and EDGAR's MACOM page still listed the newest such filing as October 1 when checked on October 21 [9][10].

*Chart: **Every published price target sits above the rout-week close** Bar chart showing MTSI's October 16 close of $262.24 below the lowest analyst target of $300, the $395.33 consensus and the $475 high target*

*US dollars. Targets from 16 covering analysts; close from the week ended October 16, 2026. Source: Longbridge weekly recap. [6]*

## The November print settles it

The sell side has not followed the tape down: sixteen analysts, none rating the stock below hold, a consensus target of $395.33 and a floor of $300, itself 14 percent above the rout-week close, for a stock at roughly 83 times trailing earnings [4][5]. If the front end is the binding constraint, that multiple sits on a guide stepping EPS up 41 percent; if the buyers' funding is the constraint, component makers get cut before any module backlog can show it [4][5].

The fiscal Q4 report, estimated for November 5, carries the two numbers that decide: whether $415 to 425 million of revenue lands, and what the first fiscal 2027 guide says about hyperscaler orders [4]. The market has stopped asking whether the parts exist and started asking who pays for them.

## Takeaway

MACOM shipped the front end that OCP research still calls unavailable and guided fiscal Q4 up 41% in EPS, but a week of CoreWeave credit fear cut the stock 20.55% without touching the company news; the November 5 report and the first fiscal 2027 guide decide which constraint is real.

## Sources

1. [GlobeNewswire via StreetInsider, MACOM Introduces 3.2T Chipset Solution for High Speed Optical Connectivity, 17 September 2026](https://www.streetinsider.com/Globe+Newswire/MACOM+Introduces+3.2T+Chipset+Solution+for+High+Speed+Optical+Connectivity/27073085.html)
2. [FUNDA, Research|Optics: OCP 2026 Points to NPO Adoption and New Demand from Copper Replacement, 21 October 2026](https://fundaai.substack.com/p/researchoptics-ocp-2026-points-to)
3. [MACOM Technology Solutions, fiscal Q3 2026 earnings release, Exhibit 99.1 to Form 8-K, SEC EDGAR, 6 August 2026](https://www.sec.gov/Archives/edgar/data/1493594/000149359426000036/ex99_1earningsreleaseq3fy26.htm)
4. [StockAnalysis.com, MACOM (MTSI) stock overview and news feed, retrieved 21 October 2026](https://stockanalysis.com/stocks/mtsi/)
5. [MACOM Technology Solutions quarterly figures from its SEC filings, retrieved 21 October 2026](https://www.sec.gov/cgi-bin/browse-edgar?action=getcompany&CIK=0001493594)
6. [Longbridge, Weekly Recap | Macom Tech -20.55%, chip sector leads sell-off, week ended 16 October 2026](https://longbridge.com/en/news/302173332)
7. [Stocktwits, Short Sellers Have Earned $32B Over The Past Week Amid Chipmaker Selloff: Report, 16 October 2026](https://stocktwits.com/news-articles/markets/equity/short-sellers-have-earned-32-b-over-the-past-week-amid-chipmaker-selloff-report/cZxKgyLRBtR)
8. [The Inference, Ciena Promised 30% Growth Through 2029. Four Executives Sold $2.6 Million of Stock Mid-Slide., 20 October 2026](https://theinference.org/article/ciena-promised-30-growth-through-2029-four-executives-sold-2-6-million-of-stock-mid-slide)
9. [Transcript Daily, MACOM Technology Solutions: Thurston Springer Miller Herd & Titak Inc. Trims Stake, 14 October 2026](https://transcriptdaily.com/2026/10/14/macom-technology-solutions-holdings-inc-mtsi-stock-thurston-springer-miller-herd-titak-inc-trims-stake.html)
10. [Investing.com UK, Form 144 MACOM Technology Solutions Holdings For: 18 October, 19 October 2026](https://uk.investing.com/news/stock-market-news/form-144-macom-technology-solutions-holdings-for-18-october-93CH-4916446)


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MACOM sells the optical front end OCP says suppliers still lack, and CoreWeave credit fear cut the stock 20% — The Inference. Canonical: https://theinference.org/article/macom-sells-the-optical-front-end-ocp-says-suppliers-still-lack-and-coreweave-credit-fear-cut-the-stock-20