Investors are optimistic on November 9 morning as stocks soared on news that Joe Biden will become the 46th President of the United States and that a late-stage Pfizer vaccine might soon be ready for use.

The S&P 500 is up roughly 3% in morning trading, with the Dow soaring over 4% as many of the more beaten-down names jumped on positive developments for a potential vaccine.

The stock gains November 9 come after a strong week for markets, as those like Michael Reynolds, investment strategy officer at Glenmede Trust, argue, “In a sense, the market has already reacted to what it’s seen as the most likely outcome” of the election.

Indeed, despite a nail-biting four days awaiting the election outcome, markets soared roughly 7%—with the S&P 500 just shy of its all-time high—as investors priced in a Biden victory and a split Congress.

Then pharma giant Pfizer and German firm BioNTech announced early November 9 that their coronavirus vaccine, currently in late-stage trials, prevented 90% of infections in participants—sending global markets and U.S. stocks (save for stay-at-home names) higher.

If it turns out to be legitimate, the Pfizer vaccine could be a “game changer,” Chris Zaccarelli, chief investment officer for Independent Advisor Alliance, said in a note on November 9, and “to the extent that consumer spending and economic activity have been suppressed by concerns of the increasing COVID cases, anything that can reverse that trend will be welcomed by the markets.”

An election “sweet spot”

But apart from the encouraging early report on the vaccine, the election result over the weekend finally gives investors some certainty about the next administration following a tumultuous year, an ongoing pandemic, and a contentious election season that saw stocks fall and soar from one week to the next.

“We’re seeing some of those risks resolve, politically certainly, and that’s meaningful,” Brad McMillan, chief investment officer for Commonwealth Financial Network, tells Fortune. “Political uncertainty is only going to ratchet down as we move forward, once we get through the Georgia elections, [and] that’s going to help,” he adds, referring to the runoff elections for two Senate seats in Georgia.

Though President-elect Biden is projected to secure the White House handily, Democrats in the Senate haven’t had such decisive victories. The likelihood of a Blue Wave, or a Democrat-controlled House and Senate, has dimmed in recent days, though the Senate races are tight, and Democrats could still secure the necessary seats to control the chamber in January.

But for markets a split Congress scenario would be the “sweet spot,” McMillan says.

Indeed, “the legislative environment, what can actually get done in Washington, matters more” than the President for investors, LPL Financial’s Jeff Buchbinder recently told Fortune. A split Congress would likely quell some of the bigger policy changes President-elect Biden has proposed and “has major implications for tax policy, which is probably the No. 1 market issue with regard to the election,” Buchbinder argued.

Even if Democrats are able to eke out enough seats to hold a 50/50 split with Vice President–elect Kamala Harris holding the tiebreaker vote, those like Reynolds aren’t convinced it will make the Democrats’ policy proposals all that much easier to pass with such slim margins.

“[The Democrats would] really have to thread the needle if they’re going to try to get anything through,” notes Reynolds. “It’s a difficult environment to maneuver some of these very large changes Biden has been putting forward, whether it’s changes to the Affordable Care Act or the tax increases they’ve been talking about.”

In other words? Investors are likely already breathing a sigh of relief that more aggressive policies, in their view, will be avoided.

For now, strategists say, all eyes on the Street are turning to another fiscal stimulus package to boost the recovery further and any ongoing vaccine news that could signal turning the corner on the coronavirus. Though it’s possible another stimulus package could come during the lame-duck session before the next Congress sits in January, some economists find it unlikely.

Glenmede’s Reynolds argues, “The way things are going now, we perhaps get a smaller package that sort of is a stopgap measure to make sure, in the short run, people are getting what they need with enhanced unemployment insurance, or if they do another round of stimulus checks.”

But should further evidence of a successful vaccine hit the wires, those like Brian Price, head of investment management for Commonwealth Financial Network, note the Pfizer news “is coming at a time when the number of daily cases is increasing at a worrisome rate, so any positive news that could potentially reverse these trends will be viewed favorably by the market.”

Indeed, Wall Street firms like UBS are now looking beyond the race for the White House: “Election Day is behind us, but corporate earnings can still improve with further stimulus, an end to COVID-19, and continued economic recovery. Fiscal stimulus should be supportive even if it is less than expected, and we still expect a vaccine to become widely available by the second quarter of next year,” strategists at UBS wrote in a note on November 6.

In the meantime, one thing investors can likely expect with a Biden administration? Less Twitter noise roiling the stock market. Says Reynolds: “A little bit more stability in terms of executive policy is something that will be a positive in a Biden administration.”