Key Highlights

● MACOM traded at about $234.69 on October 22 amid a chip selloff.

● The move came without company-specific news.

● Lam guided December-quarter revenue to $8.6 billion, plus or minus $400 million.

● The chip index closed just above its 200-day moving average.

MACOM Technology Solutions (NASDAQ:MTSI) plunged on Thursday, October 22, 2026, as the semiconductor selloff that started among the industry's giants spread to mid-sized chip makers. The stock traded at about $234.69, making it one of the biggest decliners in the S&P MidCap 400.

The drop came without company-specific news. MACOM moved with its sector.

A sector-wide rout

The Philadelphia Semiconductor Index posted its biggest one-day decline since June 23. MACOM was among the chip names that plummeted, along with AMD (NASDAQ:AMD), Monolithic Power Systems (NASDAQ:MPWR), Vishay Intertechnology (NYSE:VSH) and Semtech (NASDAQ:SMTC).

Two developments drove the selling. First, Lam Research (NASDAQ:LRCX), one of the world's largest makers of chip-manufacturing equipment, gave December-quarter guidance of $8.6 billion in revenue, plus or minus $400 million, with a midpoint slightly below what many investors had hoped for. On its call, Lam warned that upstream parts shortages and certified clean-room constraints "continue to curb manufacturing velocity" and will persist into 2027.

Lam's chief executive said those constraints would "limit chip makers and equipment companies' ability to fully meet end demand" into 2027.

Meta's spending shock

Second, the report from Meta Platforms (NASDAQ:META) late on Wednesday raised fresh questions about the cost of the artificial-intelligence build-out. Meta narrowed its 2026 capital expenditure range to $135 billion to $145 billion and reported negative free cash flow, which marked its first cash outflow in more than a decade.

Nvidia (NASDAQ:NVDA)'s chief executive added to the unease. "The demand of the capital is much greater than the availability of the capital," he said.

For chip companies tied to AI data-center spending, the combination of supply constraints and financing worries was potent, and MACOM's shares moved with the group.

Big and small, all down

The damage was broad. Lam Research itself plunged, while KLA (NASDAQ:KLAC), Applied Materials (NASDAQ:AMAT) and ASML (NASDAQ:ASML) also fell sharply. Nvidia closed at $212.21 and was one of the biggest drags on the S&P 500, according to market reports. Intel (NASDAQ:INTC), AMD, SanDisk (NASDAQ:SNDK) and Marvell (NASDAQ:MRVL) each fell steeply.

The Nasdaq Composite fell 694.00 points to 26,008.86, its steepest drop since June 5, ending a seven-session winning streak. The S&P 500 lost 93.74 points to 7,663.43, its worst day since July.

Money moved elsewhere

The selling in chips did not reflect a broad collapse. About two of every three S&P 500 stocks rose, according to market reports, and the Dow Jones Industrial Average edged up 11.89 points. Consumer staples posted their best day since April 2025, and health care hit a record.

Even so, the semiconductor index closed just above its 200-day moving average, a level many technical traders watch closely.

MACOM Awaits Its Own Earnings Report

For MACOM, the next catalyst is its own earnings report, which will show whether demand remains firm and whether supply constraints are affecting its business.

For the chip sector broadly, next week is pivotal. Microsoft (NASDAQ:MSFT) and Alphabet (NASDAQ:GOOGL) report on October 28, and Amazon (NASDAQ:AMZN) and Intel follow on October 29. Their spending plans and commentary on AI demand will help determine whether Thursday's selloff deepens or proves to be a pause.