October began with the S&P 500 at a record high and ended with the stock market in fear. The fear had several sources that partly coincided: AI-related stocks that fell in waves, France that became an interest rate risk for all of Europe, and oil that remained at high levels. The Fed and ECB left interest rates unchanged, while almost everyone expects the Riksbank to raise in November.

When stocks fell, US bonds rose, something they almost never did in September. At today's interest rates, the argument that there are no alternatives to stocks no longer holds.

We'll monitor whether bonds continue to act as a counterweight, and why interest rates fall when they do. Lower inflation and weaker growth can produce the same interest rate movement but mean different things for the stock market.