The U.S. stock market is tracking the 1989 Japan bubble. When that bubble burst, their market didn't recover for 40 years. So what's going on?

In the 1980s, Japan saw a rapid surge in stock and real estate values. It was called "The Everything Bubble."

The math was simple but dangerous.

• Low interest rates flooded the market with cheap money.

• Companies used that money to buy stocks.

• Rising stock prices increased corporate valuations.

• Higher valuations let those companies borrow even more money to buy even more stocks.

Real estate in Tokyo was so expensive that the grounds of the Imperial Palace were worth more than the entire state of California! It was a perfect circle that worked till it didn't. In 1989, the market crashed 50 percent. Then it dropped a bit more. It did not fully recover for almost 40 years.

Today, the S&P 500's trajectory looks the same. We see the same pattern of cheap money, massive debt, and a belief that prices can only go up. But there is one major difference this time: AI productivity and companies with real cash flows.

While Japan was fueled by a real estate frenzy, the U.S. is fueled by companies like Nvidia and Microsoft generating massive cash flow. The question is whether that productivity can grow fast enough to outrun the debt.

At the same time, we're also face a shrinking workforce and rising social costs. How will these forces work together?

The goal is not to predict a crash but to prepare for any eventuality. I broke down the full data on the great melt-up and what it means for your portfolio: