Stocks are trading mixed on the second trading day in December, following Monday's record highs for the S&P 500 and Nasdaq.

The S&P 500 ticked down 0.04%, while the tech-heavy Nasdaq Composite added 0.14%. The Dow Jones Industrial Average dipped 0.17%. The Russell 2000 Index fell 0.8%.

S&P 500 big stock movers today

Five S&P 500 stocks making big midday moves are:

• Palantir (PLTR)  +7.3%

• Axon Enterprise  (AAXN)  +4.5%

• Molina Healthcare  (MOH)  +3.8%

• Sysco  (SYY)  +3.5%

• AT&T  (T)  +3.4%

The worst-performing five S&P 500 stocks with the largest midday drop are:

• Intel  (INTC)  -5.6%

• Microchip Technology  (MCHP)  -5.4%

• On Semiconductor  (ON)  -5.2%

• Seagate Technology  (STX)  -4.7%

• FedEx  (FDX)  -4.0%

Stocks also worth noting include:

• Nvidia  (NVDA)  +0.4%

• Tesla  (TSLA)  -2.2%

• Apple  (AAPL)  +1%

• Amazon  (AMZN)  +1.1%

• Super Micro Computer  (SMCI)  -1%

AT&T pops on optimistic outlook

AT&T shares surged 4% to a three-year high midday after the telecom-service giant outlined plans to boost earnings and cash flow while focusing on 5G and fiber network expansion.

The Dallas carrier aims to double its fiber network and expand its 5G coverage to 200 million homes, targeting 50 million fiber locations by 2029.

Financially, the company plans $22 billion in capital investments over the next three years and expects free cash flow to reach $18 billion by 2027.

Related: AT&T stock jumps as CEO Stankey defends dividend in new growth plan

AT&T also affirmed its commitment to its $1.11-per-share dividend and plans to return $40 billion to shareholders through dividends and buybacks by 2027. It raised the lower end of its 2024 profit forecast to $2.20 to $2.25 per share.

New Street upgraded AT&T to buy from neutral with a $32.50 price target, thefly.com reported. The investment firm noted that AT&T's guidance and strategic focus closely matched its recent report, adding that the guidance is generally better than expected.

Intel drops after CEO exits

Intel lost 5% midday after yesterday’s announcement of the retirement of CEO Pat Gelsinger. The company dipped 0.5% on Monday.

Reuters reported that the chipmaker was considering former board member Lip-Bu Tan as CEO. Tan joined Intel’s board in September 2022 and began overseeing manufacturing operations a year later.

Related: Pat Gelsinger: Intel CEO’s net worth & salary as he steps down

Oppenheimer said Gelsinger's successor would face structural headwinds, including lagging foundry technology, declining market share in central processing units, and missed opportunities in AI. Bank of America sees a greater possibility that Intel will consider separating its foundry business, thefly.com reported.