Have you ever wanted to talk to someone from back in time about the US stock market?
What if you could go back to 1930 and ask someone how they think the market would perform over the next 100 years?
I was able to get the opportunity.
Through an AI chatbot, that is.
Some researchers have been building a large language chat model “trained on pre-1931 text”.1 They call it Talkie.
I posed this question: “What will the average rate of return for shareholders of stocks in the largest 500 American companies be over the next 100 years?”
Here is a portion of the answer—and I confirmed that the results are before inflation:
The average rate of return to the holders of shares in the largest 500 American companies will probably be about 6·3 per cent. per annum. The estimate is based upon a calculation which allows for all descriptions of enterprise, from mammoth "trusts" to petty local "tramways.”2
So, I decided to ask Claude’s Opus 4.7 chat the same question about the next 100 years and to answer in two sentences.
Here is what it said:
Probably somewhere in the 6–8% nominal / 3–5% real range — lower than the historical 10% because today's valuations are elevated and the 20th-century U.S. tailwinds (winning two world wars on home soil, becoming the reserve currency, etc.) likely won't fully repeat. But honestly, nobody knows — anyone giving you a precise 100-year number is exceeding what the underlying data can support.3
Interesting, isn’t it, that it lands close to what the 1931 version predicted.
We don’t know what will happen the next 100 years, but we do know what has happened the last nearly 100 years.
So how did 1930 AI do?
Far too pessimistic. The average annualized total return was 10%.4
The current AI is also a touch pessimistic for the next 100 years, but the AI does say two very important words: “nobody knows”. I’ve written the same before.
Don’t base your investment moves on AI or analyst predictions.
Get a plan and act on it.
If you or someone you know needs help and want to talk to a personal financial advisor—not a machine—reach out to us.
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Sources:
1. Via chat on April 28, 2026. Accessed online.
2. Ibid.
3. Via chat on April 30, 2026. Accessed online.
4. Data from chart above referenced by Peter Mallouk via his LinkedIn post published on April 28, 2026. Accessed online.