I've always said :
- that short-term stock market trends are not a reliable indicator of the general state of the economy, and
- presidents generally have little impact on short-term economic conditions in any event. So I don't claim that the stock market rally today "proves" Biden will be better than Trump.
But it's strange that Trump is trying to take credit for a rally that was obviously caused by the news that it's now clear he won't be able to stay in power! It would be more logical for Trump to cite the rally as "proof" that Biden serves the interests of the evil "globalist" financial elite of stockholders at the expense of the white working class "real Americans" who form a big part of Trump's base. It's a flawed argument. But less ridiculous than what he's actually saying!
Of course, logical consistency is rarely a priority for politicians, and even less for Trump than for most others.
I will note that I also hate how people talk about the president's "economic performance" right after election day. It has to take a year or more for any effects from a decision or law to ripple out into the economy. You gotta lag that analysis. The whole first six months of Trump was me telling conservatives crowing about economic growth: "what did he do?" He finally got a tax bill so I switched to: "how fast do you think these things take effect?"
I often think of this Bill Buckley quote when I get in these debates:
"The country's economy is booming, and the nation is technically at peace. It is suggested that the economy booms because every morning before breakfast President Johnson gets up and produces a hundred thousand cars, a million refrigerators, and a billion ears of corn."
Both sides do this!
I do think there's some reason to think many investors prefer Biden to Trump, and that it's not just a matter of preference for stability. A good many more or less said so over the last few months, and survey data indicates Wall Street leaders have become increasingly Democratic over the last few years, thanks in part to their aversion to Trump. It is indeed true, however, that the stock market rose under Trump, however (as was also the case under Obama).