Best Rebalanced Threshold for a 50% SPY and 50% Cash Portfolio

Rebalanced between cash and SPY seems to be a good strategy. This article is about studying with which threshold does it perform best.

Rebalacing with 20% Threshold

The standard devision of returns decreases with the decrease rebalanced thresholds.
The mean returns increases with the increase of rebalanced thresholds.
There is no significant corrlation between rebalanced thresholds and Sharpe ratios.