inflationary adjustment factor (IAF): 1. One plus the percentage change in the inflation index from the base-line-date. 2. The conversion factor used to convert MR$ into USD, such that MR$ x IAF = USD. 3. The inverse factor by which USD can be converted into MR$, such that USD/IAF = MR$. 4. The IAF is meant to express the relative purchasing power values of these currencies, which should not be confused with the currency exchange rate. See: currency exchange rate. 5. The indexed ratio; which is the term used by the U.S. Treasury for the TIPS, instead of inflationary adjustment factor.