Limited Rebalancing for SACEMS?

A subscriber observed that backtesting of momentum-based trading systems typically assumes perfect rebalancing each month whether or not they select new assets. Would delaying rebalancing until new assets are selected improve strategy performance? To investigate, we compare the following two versions of the Simple Asset Class ETF Momentum Strategy (SACEMS) equal-weighted (EW) Top 2 portfolio:

1. Rinse-and-Repeat – each month rebalance the two positions to equal weights. This is the assumption for tracked SACEMS.
2. Let-It-Ride – rebalance the two positions to equal weights only when the strategy selects two new assets. In other words, as long as at least one of the two selections is a holdover from the prior month, let the two positions drift away from equal weights.

Using monthly returns for the top two SACEMS selections during July 2006 through February 2024, we find that: (more…)