Lumentum's stock performance ranks sixth in the S&P 500 this year. Now the optical company is set to join the Nasdaq-100.

Lumentum shares have gained nearly 150% so far this year.

Lumentum Holdings is about to become the newest member of the Nasdaq-100 index, further signaling the optical-technology maker's rapid ascent.

Lumentum $(LITE)$, now worth $70 billion, will join the Nasdaq-100 before the opening bell on May 18, Nasdaq Global Indexes announced late Friday. The company is set to replace CoStar Group $(CSGP)$, a real-estate analytics company whose market value has plunged to about $13 billion as its shares have lost half their value so far this year.

It's a validation moment for Lumentum, which only joined the S&P 500 SPX in March. At the time of the S&P 500 announcement, Lumentum said in a release that the move reflected its "substantial growth and corresponding increase in market capitalization."

Optoelectronics technology has become critical for the artificial-intelligence boom, and investors have taken notice. Lumentum's 145% stock surge this year ranks sixth among current S&P 500 components. That comes on the heels of a 339% increase in 2025.

Lumentum's transceivers and lasers help enable connectivity for the AI ecosystem. On the company's earnings call earlier this week, CEO Michael Hurlston noted that Lumentum's technology has seen increased demand thanks to scale-across networks that necessitate high-bandwidth connections across data centers.

"To enable this, we provide critical hardware components that provide high-density optical interconnects while meeting aggressive power and performance targets," he said.

The Nasdaq-100 is made up of the 100 largest nonfinancial companies whose shares trade on the Nasdaq COMP. More than 200 investment vehicles with a combined $600 billion-plus in assets under management track the index, according to the Nasdaq release. While the index doesn't exclusively house technology companies, its tech-heavy nature makes it a major gauge of the sector's performance.

"We view the Nasdaq-100 as a preferred play on the AI buildout relative to more traditional large-cap growth indexes," Citi strategist Scott Chronert said in a note to clients on Friday, citing how the index has outperformed others focused on growth stocks this year to date. It also trades at a forward price-to-earnings multiple of 25, which Chronert said is "not inexpensive" but also near where the index traded prior to the pandemic.

The Nasdaq-100 has risen about 16% so far this year, twice the gain of the S&P 500.