Lumentum Holdings and Ciena Corporation fell about 10% Monday as Meta Platforms and oil rose

Lumentum Holdings fell 9.8% and Ciena Corporation fell 10% on Monday, while Meta Platforms rose 3.4% and oil finished higher. The S&P 500 slipped 0.05% to 7,807.79.

Optical stocks

Lumentum closed at $995.41. The Roundhill Photonics & Optics ETF, —LYTE, fell 7.7%. Lumentum is its largest stock holding, and Ciena is in the fund as well.

Lumentum had risen 5.2% on Friday after chief executive Michael Hurlston told Bloomberg the company was completely sold out of key optical parts.

Broadcom Inc. chief executive Hock Tan, speaking at an event in Singapore, likened many artificial-intelligence investors to casino gamblers, Bloomberg reported. "A lot of investors have no clue what they are investing in," he said. They "set very extreme expectations only to find out that it's almost like they are in a casino."

The Motley Fool wrote Monday that the comments appeared to generate a pullback in the main artificial-intelligence infrastructure stocks.

Broadcom, the chip company Tan runs, fell 1.9%.

Memory chips

Micron Technology fell 3.9% to $989.04, and Sandisk fell 6% to $1,487.33. Investor's Business Daily tied the drop to competitive pressure from ChangXin Memory Technologies, a Chinese memory-chip maker based in Hefei. President Cao Kanyu, at an industry event in Shanghai over the weekend, described a denser memory-cell design and a server-memory product planned by the end of 2026.

The VanEck Semiconductor ETF, ASMH, fell 2% to $590.99. Nvidia, its largest holding, fell 1.3%. Micron is in the fund, and it fell more than Nvidia.

Meta's models and oil

Meta closed at $742.96, against a 0.44% drop in the Nasdaq Composite. The company introduced Muse Wonder and Muse Wonder Full, artificial-intelligence models for personal and professional agents. It called them its most capable, with what it said was state-of-the-art performance.

West Texas Intermediate crude traded as low as $89.61 a barrel and was at $93.19 at 4:36 p.m. Eastern time, up 1.5% from Friday's settlement price. FXStreet reported that it fell early after President Donald Trump said Russia and Ukraine had agreed to halt attacks on energy sites, then recovered as attacks on Saudi Arabia revived supply fears.

The United States Oil Fund, LP, BUSO, which holds near-term crude futures rather than oil producers, rose 1.9% to $151.03.

The State Street Energy Select Sector SPDR ETF, AXLE, rose 1.4% to $66.02 after trading at $66.42, a 52-week high. Exxonmobil Holdings, the oil producer and its largest holding, rose 1.9%, and Chevron rose 1.4%.

Chipotle, IonQ and eBay

Chipotle Mexican Grill fell 3.8% to $30.40 after Starbucks said it is not buying the chain. The denial followed an October 8 Financial Times report that Starbucks, run by former Chipotle chief executive Brian Niccol, had explored a takeover. Reuters reported that the Financial Times story sent Chipotle up more than 7% and Starbucks down about 3% last week.

"As a matter of policy, we don't comment on rumors and speculation, but we want to be clear we are not buying Chipotle," a Starbucks spokesperson told Reuters.

Starbucks rose 1.7%.

IonQ, a quantum computing company, fell 9.1% to $36.27 after agreeing to buy cybersecurity firm Elisity for up to $1.3 billion in stock, the company said.

eBay traded as much as 5.9% higher after Morgan Stanley analyst Nathan Feather named it a top pick and raised his price target to $132 from $127. He estimates live selling is driving more than 40% of the company's growth in the value of goods sold. The shares closed up 2.2% at $114.65.