• Rubrik, a nine-year-old data security software vendor, filed to go public.
• Microsoft will begin selling its chat and video app Teams separately from its Office product.
• United Airlines is asking its pilots to take voluntary, unpaid time off next month as it grapples with delivery delays of Boeing aircraft.

Here are the most important news items that investors need to start their trading day:

1. A new quarter

The Dow Jones Industrial Average slipped 0.6% Monday to start the second quarter as traders weighed new inflation data amid fears the market rally could slow down. The S&P 500 fell just 0.2% while the tech-heavy Nasdaq Composite rose 0.11%. Investors are cautious about when the Federal Reserve will meet their 2% inflation target and begin cutting rates. On Friday, Core PCE showed that inflation climbed 2.8% on a 12-month basis in February. Follow live market updates.

2. Going public

The IPO market is showing some signs of life after a lull dating back to the end of 2021. Rubrik, a nine-year-old data security software vendor, filed to go public on Monday. The company began by selling hardware that could back up data and has now evolved to the cloud where its software "detects, analyzes, and remediates data security risks and unauthorized user activities," according to its IPO prospectus. Rubrik plans to trade on the New York Stock Exchange under the ticker symbol "RBRK."

3. Teams splitting up

Microsoft will begin selling its chat and video app Teams separately from its Office product. The move comes six months after it unbundled the products in Europe to avoid a potential EU antitrust penalty. The split could be a boost for Salesforce-owned Slack, which filed an antitrust complaint against Microsoft with the European Commission in 2020, and Zoom. Analysts at Mizuho Securities said in a Monday note that "while customers believe Zoom is a superior platform vs. Teams" and other vendors, "the bundling of MS Teams to Office 365 has always been enticing for customers to consider Teams."

4. Net loss

Shares of Trump Media & Technology Group plunged 21% Monday after the company tied to former President Donald Trump reported a loss of $58.2 million in 2023 on just $4.1 million in revenue. The Truth Social operator's stock is down almost 40% since its high last week after becoming publicly traded. The loss appears to mainly come from $39.4 million in interest expense, according to an SEC filing. Trump, who is currently not permitted to sell his stock in the company for six months, owns shares valued at about $3.8 billion as of Monday's close.

5. Taking time off

United Airlines is asking its pilots to take voluntary, unpaid time off next month as it grapples with delivery delays of Boeing aircraft. The carrier expects to receive fewer Boeing 737 Max 8 and 9 planes this year than previously contracted. United's pilots union said it anticipates the airline to offer more time off "for the summer bid periods and potentially into the fall." The request is the latest example of how Boeing's production problems and safety crisis are impacting the airline's growth plans.

— CNBC's Pia Singh, Samantha Subin, Jordan Novet, Dan Mangan and Leslie Josephs contributed to this report.

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