What a Republican sweep in Congress could mean for the stock market—in one chart

Former President Donald Trump has won the 2024 election, sweeping into office on a wave of support for Republican candidates.

NBC News reports that the previously Democrat-controlled Senate will have a Republican majority. It's too early to determine which party will win the majority in the House of Representatives, but should Republicans retain control, the party will be in position to set forth the agenda that Trump laid out on the campaign trail.

For stock investors, the occupant of the Oval Office doesn't matter much. After all, the S&P 500 has gone up during 17 of the last 20 four-year presidential terms.

But some investors may be eying the pending House races closely.

"What tends to do better for investors is not so much who is in the White House. It's the makeup of Congress," says Ryan Detrick, chief market strategist at the Carson Group.

Specifically, stocks tend to do better with a divided government. From 1951 through 2023, the S&P 500 has returned an annual average of 8% under single-party rule, compared with a 9.9% average gain when different parties control the presidency and at least one chamber of Congress, according to data provided by the Carson Group.

A divided Congress in particular tends to bode well for investors, with average yearly gains of 15.7% under Democratic presidents and 13.7% under Republican presidents.

Should the S&P 500 finish out 2024 up from the previous year (it's currently up about 25%), it will mark 14 consecutive years of positive returns under split Congresses.

The economy drives stocks, not politics

It's impossible to say exactly why stocks tend to outperform under divided governments, but it may have to do with the idea that gridlock keeps legislators from pulling levers that will have drastic effects on the economy, says Detrick.

"There's not too much power one way or the other, not too much spending one way or the other," he says. "There are checks and balances, the way our forefathers wanted things."

Still, historical returns are no guarantee of future results. What's more, the outcome of the recent election has far less bearing on stock prices than the economic fundamentals that drive them. And the government that comes into power under Trump is set to inherit a favorable economic picture, says Detrick.

"Initial [jobless] claims have come back to the lowest levels since May, so we still have a solid labor market," he says. "We still have a pretty solid economy being led by record earnings."

Things can change quickly, of course. A unified Congress could potentially take power and pass sweeping legislation that would "upset the apple cart," Detrick says. But even then, you're likely better off paying attention to the things that have direct impact on the economy, like central banking policy.

"Right now, the Fed is cutting rates," Detrick says. "That matters much more to us as investors versus something that Congress is up to." Lower interest rates directly impact the economy by making it easy for consumers and businesses to get access to credit. They're also, in this case, a response to an assessment on the part of the Fed that inflation is cooling.

In other words, if you're stressing today about the election's potential impact on your finances, it's worth remembering that, while policy can have an effect on your portfolio, it's far from the deciding factor for how things play out in the markets.

"The reality is that the economy matters more," says Detrick.

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