The Dow Jones Industrial Average and S&P 500 fell on Monday following a record-setting session as traders worried about rising coronavirus cases and searched for clues on additional fiscal aid.

The 30-stock Dow closed 148.47 points lower, or 0.5%, at 30,069.79 and snapped a four-day winning streak. The S&P 500 dipped 0.2% to 3,691.96. The Dow and the S&P 500 had closed at all-time highs on Friday. The Nasdaq Composite, meanwhile, rose 0.5% to 12,519.95 and hit a fresh record high.

Value stocks — which had been on a tear recently — lagged their growth counterparts on Monday as uncertainty grew over the near-term economic outlook. The iShares Russell 1000 Value ETF (IWD) dipped 0.6%, and the iShares Russell 1000 Growth ETF (IWF) climbed 0.4%.

Intel was the worst-performing Dow stock, falling 3.4%. The energy sector led the S&P 500 lower, sliding 2.4%. Facebook rose 2.1%, and Apple gained 1.2% to lead the Nasdaq higher. Tesla also contributed to the Nasdaq's gains, advancing 7.1% and reaching an all-time high.

"In the near-term, the risk of a modest equity market pullback has risen because the worsening virus situation in the U.S. could spur a positioning unwind," wrote Goldman Sachs equity strategists in a note Monday. "Although vaccine approval in the U.S. appears imminent, increased restrictions or shutdowns in the U.S. could slow the near-term recovery in economic growth."

The U.S. has reported a record-high average number of cases over the past seven days of more than 196,200. That's up 20% when compared to the week-earlier period. The U.S. was also approaching a record-high number of daily Covid-related deaths.

Dr. Deborah Birx warned on Sunday that the escalating coronavirus cases will be "the worst event that this country will face, not just from a public health side."

The rising caseload has led to increased calls for additional fiscal stimulus. However, lawmakers are struggling to push through new legislation before year-end.

On Monday, a Democratic aide told CNBC that Congress is looking to extend government funding for an additional week to buy more time to scrape together a new relief measure. The news came after a bipartisan group of senators unveiled a $908 billion aid proposal last week.

Senate Majority Leader Mitch McConnell initially shut down the measure, but a spokesman for House Speaker Nancy Pelosi later said she and McConnell discussed their "shared commitment to completing an omnibus [spending bill] and Covid relief as soon as possible."

"At this point, the market is anticipating at least several hundred billion dollars of incremental stimulus in 2020," said Adam Crisafulli, founder of Vital Knowledge, in a note. But "whereas Washington had been a tailwind in late-Nov and early-Dec as fiscal progress occurred faster than anticipated, the whole topic is starting to become more neutral (and possibly a headwind to the extent Congress fails to deliver on investor assumptions)."

Lawmakers have been at a stalemate over additional fiscal aid for months, raising concern about the economic recovery from the coronavirus pandemic.

The increasing number of coronavirus cases has led some states and cities to re-impose stricter social distancing measures to curb the outbreak.

"Renewed lockdown restrictions in response to the third wave of the pandemic are likely to weigh on the economy in coming months, but we don't expect a double-dip," said Ed Yardeni, president and chief investment strategist at Yardeni Research. "The economy could be booming next spring if enough of us are inoculated against the virus."

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