"Alternative Realities" Simulation

Rewind  replays market history to show how price histories might have varied from the given market conditions.  The so-called "random walk" is real, but not a single stationary condition.  Individual returns are indeed highly random,  but the upward or downward bias under that randomness varies over time.

Sampling the Universe

In this context, a set of actual returns from a given period is like a sampling  from an unseen probability distribution.  Another sample from the same distribution would give a similar but not identical returns set.

Rewind takes successive samples and generates new (replacement) draws from the inferred distributions.   Returns accumulate into alternative price paths that might have occurred from the same probability sets.  Various alternative paths might be generated from the same conditions, each having trends and volatility "like" the original actual path, yet different from it. 


A specific actualized path was not the only path that could have emerged under the circumstances.  Appreciating the range of possible variants helps avoid ascribing undue meaning to the specific price path that did emerge; to be skeptical about interpreting specific prices and patterns.

Rewind can be launched on-site, or download for later local use.  This on-site model simulates recent years of S&P or Nasdaq or Russell 2000 indexes.  The download program currently runs only in Windows environment.

Note: the simulation display will blank and fill your screen upon launch; your normal (current) window display will return upon exit.

To launch the REWIND, click here, then click "Open" in the pop-up.  When finished, return to Simulations, or use the navigation field at left.

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