The S&P 500 Index (^GSPC -0.17%) took a dive late Tuesday, ending the day down 0.65%. Daily confirmed cases of COVID-19 in the U.S. have declined from recent highs, but the numbers are moving in the wrong direction in some states. Hard-hit Florida recorded nearly 200 COVID-19 deaths for Tuesday, a record for the state.

With the pandemic far from over in the United States, Congress is working on another stimulus bill. Senate Republicans introduced a $1 trillion plan on Monday, featuring a reduced federal unemployment benefit, a second round of direct payments to many Americans, and money for schools. This bill will need to be reconciled with a $3 trillion plan passed by the House in May.

Many companies are reporting earnings this week, giving investors an idea of how sales and profits held up during the worst of the pandemic. Shares of National Oilwell Varco (NOV -1.63%), F5 Networks (FFIV 0.15%), and 3M (MMM -0.91%) slumped on Tuesday after their respective reports failed to impress investors.

A man holding his head looking at a paper.

Image source: Getty Images.

After the market closed, Advanced Micro Devices (AMD -0.82%) reported strong second-quarter results that drove the stock higher in after-hours trading.

National Oilwell Varco doesn't deliver

National Oilwell Varco was a big loser on Tuesday following a disappointing report from the oilfield equipment company. The stock was down 11.1% by the end of the trading day.

The company's revenue tumbled 30% in the second quarter from the prior-year period, missing analyst estimates by $30 million. Earnings per share came in at a $0.24 loss, short of analyst expectations by $0.07. The company is working to cut costs, exceeding its targets for the second quarter. However, management said during the earnings call that demand has entirely dried up in some areas, including drill pipe repairs. National Oilwell Varco stock is now down nearly 50% since the start of the year.

F5 Networks tumbles despite earnings beat

Another stock being put through the wringer on Tuesday was F5 Networks, a provider of application delivery networking products. F5's fiscal third-quarter results came in ahead of expectations, but it wasn't enough to prevent the stock from plunging 8.7% by market close.

F5's revenue of $584 million was up 4% year over year and about $13.5 million ahead of estimates, and adjusted EPS of $2.18 beat by $0.14. The company's guidance was also solid, calling for revenue between $595 million and $615 million in the fiscal fourth quarter, along with adjusted EPS between $2.30 and $2.42.

Valuation could be one reason why F5 stock was slammed despite a positive report. Both GAAP and adjusted earnings declined in the third quarter, and the stock traded for close to 30 times GAAP earnings before Tuesday's plunge. Given the sluggish revenue growth rate and declining bottom line, investors may no longer be willing to pay such a premium for F5 stock.

3M still hurting from pandemic

Industrial conglomerate 3M also disappointed investors with its report. Total revenue slumped 12.2% as demand for certain categories, including automotive, office supplies, and healthcare elective procedures, was hit hard by the pandemic. Adjusted EPS of $1.78 was down 16.4% from the prior-year period.

The good news for 3M is that sales are starting to pick back up. Through the first few weeks of July, the company has recorded low-single-digit sales growth compared with the prior-year period. The bad news: Investors were unmoved by the improving trends. 3M stock was down 4.8% by the market close Tuesday.

After hours: AMD beat estimates

Reporting after the market close Tuesday, chip company AMD managed to beat estimates across the board with strong second-quarter results. Revenue jumped 26% to $1.93 billion, and adjusted EPS of $0.18 was up from $0.08 in the prior-year period. Analysts were expecting revenue and EPS of $1.86 billion and $0.16, respectively.

AMD's growth was driven by strong demand for its Ryzen PC chips and EPYC server chips. In the third quarter, AMD will enjoy a sales boost for its semi-custom chip business because of the ramping up of next-generation game consoles from Sony and Microsoft. The company expects third-quarter revenue of approximately $2.55 billion.

AMD stock was up nearly 9% in after-hours trading soon after the announcement.