It means that over time, classic AIM automatically steers more of funds out of stocks and into cash.
Think of AIM as a cost-averaging mechanism. Repeated add-low and reduce-high trading cost-averages down the average cost of stock over time. If you pay too much for stock in the first place, that cost averaging will at some point likely result in no difference in the average cost of stock than had you bought at the fair price level at the time of purchase.
A side effect of that is that it works both ways and if you bought at a relatively low price then the cost averaging math is such that it reduces the stock weighting over time. Almost as though AIM worked to raise the average cost of stock from a low price up to the average price.
So, generally, it doesn't matter if you overpaid or underpaid for stock, generally at some point AIM will balance towards the average (fair) price.
Very generally that means that if you started an AIM at a relatively high price level, then AIM will steer towards buying more and selling less and as such perhaps average 60% stock weighting and 40% cash weighting. If you started AIM at a relatively low price then AIM will tend to steer towards selling more and buying less, and might average 40% stock weighting and 60% cash weighting.
At some point after all three of above-average, below-average and bought at fair price levels all converge from the add-low/reduce-high trading, then thereafter the continued add-low/reduce-high cycles will tend towards less average stock weighting. If that trading adds value, then the AIM in effect becomes like having bought stock at a below average price and to compensate it tends to reduce average stock weightings accordingly. Held long enough then the stock weighting would progressively decline as a consequence of AIM's successful add-low/reduce-high trading activity.
stock exposure levels decline over time
News 
Market Data 
Discover 
