Following record high closes yesterday for the S&P 500 and Nasdaq, the former built on those gains while the latter pulled back marginally from its all-time best level. In pandemic news, U.K. regulators have the distinction of being the first to formally approve a vaccine to fight COVID-19. Meanwhile, Fed Chair Powell didn't make any waves in today's House testimony. He assured lawmakers that the central bank will continue to offer substantial support to the economy and will not pull back its measures until it is confident the accommodation is not necessary.

ECONOMIC EVENTS: In the U.S., payroll services provider ADP reported private payrolls rose 307,000 in November.

In Federal Reserve news, the Fed said in its latest Beige Book that most districts are seeing slowing employment growth, as most districts are seeing "modest or moderate" economic expansion amid the COVID-19 pandemic.

In stimulus news, House Speaker Nancy Pelosi and Senate Democratic Leader Chuck Schumer issued a joint statement on the bipartisan coronavirus relief negotiations, saying that a bipartisan framework should be the basis for talks between Democrats and Republicans.

TOP NEWS: Shares of Salesforce (CRM) and Slack Technologies (WORK) closed a respective 8.9% and 2.6% lower after the companies reached an agreement last night under which Salesforce will acquire Slack in a cash and stock deal worth $27.7B. Under the terms of the pact, Slack shareholders will receive $26.79 in cash and 0.0776 shares of Salesforce common stock for each Slack share, representing an enterprise value of approximately $27.7B based on the closing price of Salesforce's common stock on November 30. The news came alongside both companies reporting better than expected quarterly results and drew criticism about the price paid from several Wall Street analysts.

In other earnings news, NetApp (NTAP) shares jumped 9.4% after the company reported upbeat Q2 results and provided better than expected third quarter guidance.

On the COVID-19 front, Pfizer (PFE) and BioNTech (BNTX) announced that the Medicines & Healthcare Products Regulatory Agency, or MHRA, in the UK has granted a temporary authorization for emergency use for their COVID-19 mRNA vaccine, or BNT162b2, against COVID-19. Following the announcement, New York Governor Andrew Cuomo said that the state's first delivery of Pfizer's COVID-19 vaccine will "be enough for 170,000 New Yorkers," and that the state expects to receive said doses on December 15.

Meanwhile, Moderna (MRNA) shares gained 1.4%. Merck (MRK) said it divested its direct holding in the company in the first half of the fourth quarter. As such, Merck expects to record a "small" gain.

Additionally, Amazon (AMZN) was in focus after The Wall Street Journal reported that the company is in exclusive talks to acquire podcast startup Wondery, with talks currently valuing the startup at above $300M. In other potential M&A news, Axios reported that Uber (UBER) has agreed to sell its Uber Elevate unit to Joby Aviation.

MAJOR MOVERS: Among the notable losers was Ovid Therapeutics (OVID), which dropped 55.9% after its Phase 3 NEPTUNE trial of OV101 did not meet its primary endpoint. Also lower was Palantir (PLTR), which fell 12.8% after Morgan Stanley analyst Keith Weiss downgraded the stock to Underweight from Equal Weight.

INDEXES: The Dow rose 59.87, or 0.20%, to 29,883.79, the Nasdaq lost 5.74, or 0.046%, to 12,349.37, and the S&P 500 advanced 6.56, or 0.18%, to 3,669.01.