Major U.S. equities indexes were mixed to open the trading week as markets expect Wednesday's quarterly earnings report from semiconductor behemoth Nvidia (NVDA).

Although Nvidia is likely to take the spotlight, other companies, including retail giants Walmart (WMT) and Target (TGT), are set to disclose results this week as earnings season winds down. Investors will also get a look at key data on the housing market, the manufacturing sector, and consumer sentiment.

The S&P 500 advanced 0.4%, while the Nasdaq added 0.7%. The Dow slipped 0.1%, with the blue-chip index dragged down by Nike's (NKE) underperformance.

Super Micro Computer (SMCI) shares surged 15.9%, notching Monday's top performance in the S&P 500, following reports that the server and data storage provider is prepared to submit a plan that will avoid the delisting of its stock from the Nasdaq. Supermicro shares have been under pressure since the company delayed the filing of its annual report amid accusations of accounting irregularities, jeopardizing its compliance with the exchange's reporting requirements.

Shares of Henry Schein (HSIC), which distributes medical and dental supplies to health care providers, jumped 7.5%. The gains came after reports that activist investor Ananym Capital Management is encouraging Henry Schein to pursue numerous changes that could boost its stock price, including reshuffling its board of directors, improving succession plans, cutting costs, and evaluating a potential sale of its medical distribution business.

Analysts at HSBC upgraded Moderna (MRNA) stock to "buy" from "hold," indicating they view shares of the biotech firm as undervalued. Moderna shares popped 7.2% higher, clawing back a portion of the losses posted last week amid concerns about the outlook for vaccines under the incoming presidential administration.

CVS Health (CVS) announced that it will add four new members to its board of directors in a deal with activist investor Glenview Capital. Glenview amassed a significant position in the drugstore operator and has been pushing for changes to boost value creation. CVS shares added 5.4% on Monday.

Amentum (AMTM) shares plummeted 9.6% on Monday, falling the most of any S&P 500 stock. The provider of technology and engineering solutions to the U.S. government faces integration risks following its merger with a pair of divisions spun out from Jacobs Solutions (J), which closed in September.

Shares of Palantir Technologies (PLTR) fell 6.9%, giving back a portion of the robust gains posted since the analytics software firm beat quarterly sales and profit expectations in a report released Nov. 4. Monday's reversal occurred after a regulatory filing revealed that Palantir CEO Alex Karp sold 4.5 million shares of the stock, raising concerns about management's confidence in the company's upcoming performance.

Uber Technologies (UBER) shares fell 5.4% following reports that President-Elect Donald Trump could relax regulations related to self-driving cars during his second term. The prospect of establishing a federal framework for autonomous vehicles bodes well for Tesla's (TSLA) plans to launch a robotaxi network that would compete with Uber's ride-hailing business. Shares of fellow ride-sharing platform Lyft (LYFT) slipped 4.5% on Monday, while Tesla shares traded 5.6% higher.