A sign is posted in front of a Broadcom office in San Jose, California, on Dec. 12, 2024.Justin Sullivan | Getty ImagesThis is CNBC's Morning Squawk newsletter. Subscribe here to receive future editions in your inbox.Here are five key things investors need to know to start the trading day:1. Broadcom's boonOpenAI made its latest artificial intelligence partnership official yesterday, announcing a custom chip deal with Broadcom. Shares of the chipmaker closed Monday's session nearly 10% higher following news ...