During President Donald Trump's second term, the S&P 500 experienced significant volatility, marking the third-worst 100-day start to a presidential term in US history. Initially, the market surged post-reelection due to expectations of a pro-business environment, but fluctuated amid uncertainty caused by Trump's tariffs and inconsistent trade policies. The performance of the S&P 500, a key indicator of the US economy that affects retirement plans for many Americans, is being tracked against historical trends since World War II. Historically, the S&P's performance during a president's initial 100 days has been indicative of the market's annual outcome, with above-average early gains leading to significant yearly growth and below-average returns corresponding to annual losses. Investors are closely watching how Trump's trade policies, particularly tariffs, will continue to influence economic conditions and market stability in the long term.

The S&P 500 experienced its third-worst 100-day start under Trump, a situation only surpassed by Gerald Ford and Richard Nixon, highlighting significant market uncertainty during his second term.

Initially, there was a surge in the S&P 500 following Trump's reelection, driven by expectations of a strong pro-business environment, but this optimism was undermined by volatile trade policies and tariff announcements.

The S&P 500 serves as a benchmark for US economic health, tracking the largest 500 public companies and influencing retirement investments like 401(k)s, which means many Americans are indirectly affected by its fluctuations.

Historically, the first 100 days of a presidency have provided a bellwether for the market's annual performance, with early gains leading to an average annual increase of 21.1% and early losses leading to an average annual decline of 5.5%, according to CFRA Research's Sam Stovall.

Investors had initially perceived Trump's tariffs as more rhetorical than actual, but as these policies materialized, they introduced real economic implications, and the long-term effects remain uncertain.

Approximately 62% of US adults were invested in the stock market in 2024, whether directly through stocks or indirectly via mutual funds and retirement accounts, underscoring the broad impact of stock market volatility on the populace.

CNN is actively tracking the S&P 500's performance during Trump's second term, comparing it to past presidencies to provide context on its relative performance and the implications of current economic policies.