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• US stocks gained on Monday amid reports that former Fed Chair Janet Yellen would be selected as President-elect Joe Biden's Treasury Secretary.
• The news came on a day where investors cheered the data results from another COVID-19 vaccine candidate, this time from AstraZeneca.
• AstraZeneca said its COVID-19 vaccine candidate demonstrated an average efficacy rate of 70%, making it the third company to have announced vaccine data that surpassed the Food and Drug Administration's requirement of 50% effectiveness.
• Watch major indexes update live here.

US stocks jumped on Monday afternoon amid reports that former Fed Chairwoman Janet Yellen would be selected as President-elect Joe Biden's Treasury Secretary.

The news of a familiar face to investors running the US Treasury department likely helped remove some uncertainty from the market as investors weigh who will fill Biden's cabinet. 

Investors also received news of a third COVID-19 vaccine candidate that demonstrated an efficacy rate above the 50% threshold set by the Food and Drug Administration.

AstraZeneca said on Monday that its COVID-19 vaccine, developed in partnership with the University of Oxford, demonstrated an average efficacy rate of 70%. It said that while one dosing regimen was found to have an efficacy rate of 90%, another demonstrated an efficacy rate of 62%.

Here's where US indexes stood at the 4 p.m. ET market close on Monday:

• S&P 500: 3,577.59, up 0.6%
• Dow Jones industrial average: 29,591.27, up 1.1% (328 points)
• Nasdaq composite: 11,880.63, up 0.2%

Read more: Goldman Sachs says to buy these 26 stocks poised to deliver the strongest earnings growth in 2021 as the S&P 500 surges another 20%

Americans could begin receiving COVID-19 vaccines as early as December 11, an advisor to the White House's Operation Warp Speed initiative said, adding that about 70% of the population could be immunized by the summer.

On Wall Street, BlackRock upgraded its outlook for US stocks to overweight as it foresees a COVID-19 vaccine hastening the economic recovery in 2021. 

Oil prices staged a rebound on Monday, hitting their highest levels since early September. The positive vaccine news suggested demand for oil could return sooner rather than later. West Texas Intermediate crude jumped as much as 2.9%, to $43.36 per barrel. Brent crude, oil's international benchmark, gained 2.6%, to $46.12 per barrel, at intraday highs.

Bitcoin's strong rally to above $18,000 helped spur a surge in other cryptocurrency assets like ether and Ripple over the weekend.

Snapchat surged as much as 7% after it revealed 'Spotlight,' a new rival platform to Tik-Tok.

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See Also:

• Warren Buffett has kept quiet for months. The famed investor compared the pandemic to a 'hurricane,' praised the initial federal response, and called for more small-business aid at a recent private event
• Markets are headed down one of 3 paths in 2021, UBS says. Here's how investors can maximize their profits in all of them.
• MORGAN STANLEY: Buy these 21 stocks set to soar at least 50% as their earnings rebound from a COVID-19-induced rout