What does Biden’s uncertain future mean for investors? Analysts weigh in

President Joe Biden is facing calls from several House Democrats to abandon his re-election campaign, raising uncertainty about his political future and the wider 2024 race less than four months before Election Day.

In a letter to Democrats on Monday, Biden vowed to stay in the race. "The question of how to move forward has been well-aired for over a week now. And it's time for it to end," Biden said, in part.

The high-stakes dispute within the Democratic Party elevates the risk for investors attempting to anticipate the election outcome and its market implications, analysts told ABC news.

The S&P 500 – the index that most people's 401(k)s track – has moved upward in the nearly two weeks since the debate between Biden and former President Donald Trump, they noted, though the outlook could shift as the full implications come into view.

"The range of possible outcomes is as wide as anyone could've imagined," Kim Wallace, a senior managing director at data firm 22V Research, who leads a team devoted to the risks posed by policy in Washington, D.C., told ABC News. "Let's face it: markets don't like uncertainty of any kind."

Even so, most analysts that spoke to ABC News downplayed the significance of the unrest regarding Biden's candidacy, pointing to a host of other factors that influence market trends, chief among them corporate profits and economic performance. It remains unclear to what extent the turbulence surrounding Biden will affect the outcome of the race or relevant policies implemented by the victor, they added.

"Market movements rarely attach for a long time to what goes on in politics," Wallace said.

In a statement, the Trump campaign sharply criticized economic performance under Biden.

"Joe Biden has already created the worst inflation crisis in a generation," Karoline Leavitt, a spokesperson for the Trump campaign, told ABC News. "If he is given another four years to continue implementing his tax hikes, burdensome regulatory policies and wasteful spending, the economy is doomed."

"If President Trump is back in the White House, he will reimplement his America First, pro-growth, pro-job agenda to bring down inflation, interest rates, and mortgage rates and rebuild an economy that is envied by the rest of the world," Leavitt added.

The Biden campaign did not immediately respond to an ABC News request for comment.

The S&P 500 has ticked up roughly 1.5% since Biden's halting performance at the debate on June 27. Over that period, the tech-heavy Nasdaq has climbed about 3%, while the Dow Jones Industrial Average has increased 1%.

The modest rise across the major stock indexes coincides with a slight improvement in the odds of a Trump victory in November, according to FiveThirtyEight. But the performance has also aligned with a period of stock market gains that stretches back to last year.

"Since the debate, markets haven't really moved obviously in response to political considerations," Christopher Smart, managing director at the Arbroath Group, a consulting firm that specializes in geopolitical risk, told ABC News.

Bond markets have offered a notable exception to that assessment, Stephen Brown, deputy chief North America economist at Capital Economics, told ABC News. In the immediate aftermath of last month's debate, the yield on 10-year treasury bonds rose to its highest rate since early June before settling at modestly elevated levels.

Yields for long-term Treasury bonds track closely with the Federal Reserve's benchmark interest rate. The response from bond markets suggests worry that a potential Trump administration could accelerate inflation and stall interest rate cuts, Brown said.

"Investors are concerned that policies Trump has proposed – such as tariffs and maybe slightly looser fiscal policy – could cause the Fed to keep interest rates higher for longer," Brown said.

Despite limited movement in markets, the outlook could shift significantly, especially if continued unrest among Democrats appears to threaten the party's chances of winning a majority in either the House or Senate, some analysts said. Under such circumstances, they noted, a potential Trump administration could pursue its policy priorities with a higher likelihood of success.

"If you see clear signs that the Democratic Party will lose both houses of Congress and the White House, that would raise the chances of the maximalist Trump agenda," Smart said. "That's what might get people's attention."

Wallace, of 22V Research, said some investors optimistic about Republican prospects in the aftermath of the debate have seized on the so-called "Trump trade." Since Trump favors tax cuts for corporations and loose regulations, some investors anticipate that his return to the White House would boost corporate profits and stock returns, Wallace said, but he noted a concurrent risk of accelerated inflation and higher national debt.

"Whether you want to press or hedge your Trump trade, or take the other side of that trade entirely, you have very little information and data to give you an edge to develop high conviction," Wallace said, pointing to the uncertainty surrounding Biden and the broader election.

On the whole, analysts advised that investors should proceed with caution. "There's sufficient uncertainty here that could catch you offside no matter how solid you think your analysis is," Wallace said.

Brown, of Capital Economics, agreed. "At this stage, for individual investors, it's a bit too much to say they should be positioning for this," he said. "It's more about having an awareness of the range of possibilities and which ones are becoming more or less likely."

At least one analyst said investors should focus on economic fundamentals rather than worry about shifts in the political winds. The stock market underwent prolonged periods of growth under former Presidents Barack Obama, Trump and Biden, Ed Yardeni, the president of market advisory firm Yardeni Research and former chief investment strategist at Deutsche Bank's U.S. equities division, told ABC News.

"Half of the country was for and half of the country was against each of those three presidents," Yardeni said. "Yet the stock market has continued to move higher."