Here are five key things investors need to know to start the trading day: 1. The major indexes started the second half with gains, with the Nasdaq Composite hitting a record high and tech stocks like Microsoft, Apple, and Nvidia seeing increases. 2. Paramount Global is exploring merger talks for Paramount+ with Warner Bros. Discovery, potentially strengthening their position in the streaming market. 3. The Boston Celtics ownership group plans to sell the team, with a majority stake expected to be sold by the end of the year, potentially valuing the team close to $4 billion. 4. Salesforce's compensation plan for top executives, including CEO Marc Benioff, was rejected by investors following concerns raised by shareholder advisory groups. 5. President Biden and former President Trump participated in the first Presidential Debate, highlighting the ongoing political dynamics in the U.S.