NEW YORK :CoreWeave, an artificial intelligence startup backed by Nvidia, has signed a five-year contract worth $11.9 billion with OpenAI ahead of its hotly anticipated stock market launch. As part of the pact, CoreWeave will provide AI infrastructure to OpenAI, CoreWeave said in a statement on Monday, confirming an earlier exclusive report from Reuters. The deal will give OpenAI a stake in CoreWeave, which will issue shares worth $350 million to the ChatGPT maker through a private placement at