U.S. stocks traded mixed during Monday's midday session, with the Nasdaq reaching a new intraday high. Markets focused on regional bank mergers and acquisitions as well as collaboration between AMD and OpenAI. Despite the government shutdown extending into its second week, markets continued their upward momentum. Several Federal Reserve officials are scheduled to speak this week.

The Dow Jones fell 87.01 points, down 0.19% to 46,671.27 points; the Nasdaq rose 163.08 points, up 0.72% to 22,943.59 points; the S&P 500 gained 27.07 points, up 0.40% to 6,742.86 points.

Earlier on Monday, the Nasdaq reached a peak of 22,949.84 points, setting a new intraday record high.

Last week, the S&P 500 and Nasdaq rose 1.1% and 1.3% respectively, marking the fourth weekly gain in five weeks. The Dow posted its third weekly gain in four weeks, rising 1.1%.

Monday's market attention centered on the AMD-OpenAI deal. OpenAI and AMD reached a multi-billion dollar cooperation agreement to jointly develop AI data centers based on AMD processors, directly challenging NVIDIA. The four-year agreement includes AMD providing hundreds of thousands of artificial intelligence chips to OpenAI, with OpenAI committing to purchase 6 gigawatts worth of AMD chips. Starting next year, they will first purchase MI450 chips, either through direct purchase or cloud computing partners.

Additionally, OpenAI received warrants from AMD that could ultimately allow it to purchase up to 10% of AMD's shares through multiple warrant tranches.

Banking company Comerica's stock surged after Fifth Third Bancorp reached an agreement to acquire the regional bank peer for $10.9 billion in an all-stock transaction. This merger will create the ninth-largest bank in the United States by assets.

Markets anticipate more deals in the regional banking sector. Overall merger and acquisition activity is accelerating, adding fuel to the robust investment sentiment seen in this year's stock market.

The U.S. government shutdown entered its second week. Although lawmakers still haven't reached an agreement on funding to keep the government operational, investors appear unconcerned about shutdown worries. The government shutdown has delayed key economic data releases, including the September employment report originally scheduled for release last Friday.

Robert Edwards, Chief Investment Officer at Edwards Asset Management, stated: "For now, the market is ignoring the government shutdown and focusing more on earnings optimism and prospects for further Federal Reserve rate cuts. Markets tend to dismiss government shutdowns as 'Washington noise' and ignore them. Government shutdowns have typically lasted days in the past, but this one could last weeks, so investors may need to remain patient."

Edwards added: "We would view any significant market decline due to the shutdown as a 'members-only shopping day' opportunity. Even facing a government shutdown and concerns about the labor market, we still believe the S&P 500 has the potential to break through the 7,000-point threshold by year-end."

Despite the interruption in economic data releases, several Federal Reserve officials are scheduled to speak this week, including Fed Governor Stephen Miran on Wednesday and Chairman Jerome Powell on Thursday.

Focus Stocks

AMD stock soared following news that OpenAI and AMD announced a multi-billion dollar partnership to collaborate on developing artificial intelligence data centers that will run on AMD processors.

Sigma Lithium, Americas Lithium, Standard Lithium, Albemarle Corporation, and others rose broadly after reports that the U.S. government is considering taking stakes in critical metals companies.

Mining stocks generally moved higher amid reports that the Trump administration is discussing taking stakes in certain critical mineral companies.

Cryptocurrencies broadly advanced.