A recent survey by CNBC found that most investors believe the stock market will flourish in a second Trump term. But that sentiment could be nostalgic thinking at work because many remember the S&P 500's gains during much of Trump's first four years in office.

The stock market climbed to record highs in 2024, extending banner gains achieved the previous year. The S&P 500 -- the index that most people's 401(k)'s track -- climbed nearly 28% this year, as of Monday.

The U.S. stock market has defied expectations once again in 2024, with the S&P 500 surging nearly 25% and setting nine all-time highs throughout the year. This marks the second consecutive year of significant growth for the index,

History offers mixed insight. On one hand, the S&P 500 performed very well during Trump's first presidency, and some analysts anticipate strong returns in his second term driven by deregulation and tax cuts. On the other hand, the S&P 500 currently trades at an expensive valuation, which hints at turbulence in the coming months and years.