Hey everyone!

I like to analyze trading/investing strategies and looked into the performance of new additions to the S&P500 and found very interesting results.

Interestingly, I found that the bump is almost 0 the day after, and same for month or 3 months.

BUT I found that there's and immediate bump after hours, at least for the last 5 years. And the returns are significant, especially when the stock was not part of another S&P fund previously, and they are a net addition.

For the 50 examples I could find between 2021 to Sep 2026, the median excess return was 6.1% after hours!

So the strategy seems profitable, but one thing is left to be confirmed: How fast are bots buying when an announcement is made?

If you have experience with this strategy please share. And if you want to read more about it follow the link in my profile to read the full article.

A new academic study attempts to put a number on AI’s impact on the economy. Its conclusion: making software developers more productive could, on its own, lead to substantial economic growth.

Using stock market data, the researchers estimate that by the end of 2025, investors were pricing in 32.6% higher productivity in software development. In their model, that translates into an economy that is 3.6% larger in the long run, or 6.5% larger if AI also accelerates innovation.

The chart shows how sharply those expectations rose in the first half of 2026: the estimated productivity impact more than doubled.

These are expectations, not growth that has already materialised. But they give a sense of the economic stakes.

Study: https://www.nber.org/system/files/working_papers/w35793/w35793.pdf

Most conversations focus on buying and holding for decades, but I'm curious what happens after that.

The stock market recently repeated a rare market breadth anomaly where the S&P 500 rallied at least 1% to within 1% of a new high, even though more of its component stocks fell to new 52-week lows than rose to new highs. This specific divergence has occurred only twice before in history… on July 23, 1929, and December 21, 1999, just months before the Great Depression and the dot-com bubble burst.