[DickingAround]

There's just one more step; the market's value is an expectation of the future while the GDP is a 'now' metric. So while inflation is auto-adjusted (roughly) in the past, a strong expectation of inflation now can send the market cap up (and either GDP will catch up, be it natural or on inflated dollar terms) or the market will crash, or some combination of the two to bring the indicator back to earth.

[eloff]

I don't think that's correct. Stocks suffer with inflation. Interest rates rise and money moves to bonds. Credit is costlier and profits fall. Both weigh on stock prices.

Historically stocks perform poorly in times of high inflation.