S&P 500 posted a 2.5% gain on Wednesday. What history says could happen next.

The S&P 500 on Wednesday saw its best post-election day in history, jumping over 2.5% to a fresh all-time high. While the Trump trade euphoria boosted the stock-market sentiment, it also was rare.

History shows the previous ten 2.5% gains for the S&P 500 all happened in the bear market of 2022.

For example, the last time the S&P 500 rose 2.5% prior to yesterday was Nov. 30, 2022 when Fed Chair Jerome Powell confirmed that the central bank may deliver a smaller interest-rate hike in December that year. But that advance was followed by a 3.6% decline over the following week and a nearly 6% slump over the next month, according to Dow Jones Market Data.

Since 1950, the S&P 500 has averaged a 0.2% decline one week after posting a 2.5% gain, while booking an average of 0.3% advance in the following month (see table above).

However, the large-cap index has averaged a nearly 8% return six months after posting a 2.5% gain, according to Dow Jones Market Data.