US equity indexes ended higher on Monday as benchmark gauges extended rallies to records, driven by tech stocks.

* Nvidia (NVDA) and Microsoft (MSFT)-backed OpenAI announced a letter of intent for the chipmaker to invest up to $100 billion in the AI startup, enabling OpenAI to build and deploy at least 10 gigawatts of AI data centers powered by Nvidia chips, with details to be finalized in the coming weeks. Nvidia shares rose 4%.

* The Chicago Fed National Activity Index, a monthly measure of economic activity, improved to minus 0.12 in August from minus 0.28 in July.

* October West Texas Intermediate crude oil fell $0.04 to settle at $62.64 per barrel, while November Brent crude, the global benchmark, was last seen down $0.11 to $66.58.

* Oracle (ORCL) will secure the algorithm for a new US version of TikTok as part of a deal to sell the Chinese-owned app to American investors, Bloomberg reported, citing a White House official. The company also announced the promotion of Clay Magouyrk and Mike Sicilia to co-chief executive officers, while Safra Catz transitions to the role of executive vice chair on the board. Oracle shares jumped 6.3%.

* Compass (COMP) shares fell 16% after the company agreed to acquire Anywhere Real Estate (HOUS) in an all-stock deal. Anywhere Real Estate surged 46%.