Reading 31 of the Schweser has the below:
An alternative to asset allocation rebalancing is to rebalance to the extent necessary to move asset class weights back within their corridor values. One rule that would accomplish this is to move the asset class weights halfway back to their target values. Under this rule, an asset class with a target allocation of 30% and a corridor of +/− 3% that has reached a weight of 35% in the portfolio would be reduced to 32.5% of the portfolio.
But 32.5% of the portfolio is not within the corridor, since corridor is 30% +/- 3% = 29.1%-30.9%.
So why do we reduce to 32.5% when it is not within the corridor?
An alternative to asset allocation rebalancing is to rebalance to the extent necessary to move asset class weights back within their corridor values. One rule that would accomplish this is to move the asset class weights halfway back to their target values. Under this rule, an asset class with a target allocation of 30% and a corridor of +/− 3% that has reached a weight of 35% in the portfolio would be reduced to 32.5% of the portfolio.
But 32.5% of the portfolio is not within the corridor, since corridor is 30% +/- 3% = 29.1%-30.9%.
So why do we reduce to 32.5% when it is not within the corridor?