(Reuters) - CoreWeave ( CRWV ) has signed a $6.3 billion initial order with backer Nvidia ( NVDA ), the data center operator said on Monday, in a deal that guarantees that the AI chipmaker will purchase any cloud capacity not sold to customers.

Shares of CoreWeave ( CRWV ) rose 8% as the deal cements the company's position as a key Nvidia ( NVDA ) cloud partner and cushions it against any potential decline in demand for AI computing capacity.

CoreWeave ( CRWV ) operates AI data centers in the U.S. and Europe, offering access to Nvidia's ( NVDA ) GPUs, which are highly sought after for training and running large AI models.

The latest order, which requires Nvidia ( NVDA ) to purchase any unsold capacity through April 13, 2032, builds on an April 2023 agreement.

The amended agreement serves as a backstop for CoreWeave, ensuring that capacity will be leveraged irrespective of the end customer, analysts at Barclays said, adding that the incremental spending by Nvidia ( NVDA ) is seen as a healthy diversification away from the company's largest customers.

"We see this as a positive for CoreWeave ( CRWV ) given concerns from investors around the company's ability to fill data center capacity beyond its two largest customers (Microsoft and OpenAI)."

In March, CoreWeave ( CRWV ) and OpenAI agreed on a five-year contract worth $11.9 billion, under which the New Jersey-based firm provides the ChatGPT maker cloud computing capacity.

The company signed an additional agreement under which OpenAI has committed to pay up to $4 billion through April 2029.

CoreWeave ( CRWV ) in August reported a surge in demand for its cloud services in the second quarter, amid the rapid adoption of artificial intelligence tools.

However, operating expenses jumped nearly fourfold to $1.19 billion, highlighting the strain that rapid revenue growth is placing on its finances.

(Reporting by Harshita Mary Varghese in Bengaluru; Editing by Sriraj Kalluvila)