bboo

It reads "....will not meet the GIPS standards for periods after Jan 1, 2010 when firms will be required to value portfolios on the date of all large external cash flows"

My interpretation is that for large external cash flows, no more modified dietz. However, for very small (or no) cash flows it is allowed. All modified dietz does it apply the average daily return to the cash flow, so if it is not large, the outcome will not be materially different.