June 5 (Reuters) - Marvell Technology ( MRVL ) is set to join the benchmark S&P 500 index, S&P Dow Jones Indices said on Friday, sending the chipmaker's shares up 6% in extended trading.

The company will join the benchmark index later this month, after it recently cleared a key profitability hurdle riding a blistering AI-fueled rally.

The stock will replace swimming pool equipment distributor PoolCorp on the benchmark index before the start of trading on June 22.

Marvell's ( MRVL ) entry comes after it reported a GAAP profit in its December quarter and over the sum of its most recent four quarters, a criterion it had failed to meet before, making it ineligible for inclusion.

The company's shares have more than tripled so far this year, bolstered by a broader rally in chip stocks on hopes for runaway AI-related demand.

This week alone the shares gained roughly 29%, partly due to Nvidia CEO Jensen Huang calling the chipmaker the "next trillion dollar company".

Marvell ( MRVL ) and larger rival Broadcom design custom chips for cloud-computing companies' specific data center needs, a business that has grown rapidly as Big Tech companies look to reduce reliance on Nvidia's costly and supply-constrained AI processors.

In its most recent quarterly earnings, Marvell ( MRVL ) forecast its custom chip business would surpass $10 billion in revenue in fiscal 2029.

The inclusion reflects how the AI boom is reshaping major U.S. equity benchmarks, with chip and data-center infrastructure companies commanding increasingly large weights as investors bet on sustained demand from cloud providers and AI workloads.

Marvell's ( MRVL ) addition to the benchmark would trigger buying from index funds and ETFs that track the S&P 500, as passive managers are required to hold constituents in line with their benchmark weights.