The funds are managed on a daily basis with cash flow used to ensure the asset allocation remains in line with the target portfolio. This use of cashflow avoids the need for wholesale rebalancing that can incur unnecessary transaction costs.
On a quarterly basis, the long term strategic asset allocation is updated. At this point, the investment team will look at the potential changes to determine whether the costs / benefit analysis warrants a change to the portfolio. This approach limits the risk of trading where there is no discernable benefit in incurring additional transaction costs.