$ISHARES MSCI INTL MOMENTUM FACTOR ETF(IMTM)$ 与 $ISHARES MSCI USA MOMENTUM FACTOR ETF(MTUM)$ 的动量因子计算方法：
The Underlying Index is designed to reflect the performance of an equity momentum strategy that emphasizes stocks with high price momentum, while maintaining reasonably high trading liquidity, investment capacity and moderate index turnover. A risk-adjusted price momentum, defined by MSCI as the excess return over the risk-free rate divided by the annualized standard deviation of weekly returns over the past three years, is calculated for each security in the Parent Index over 6- and 12-month time periods. The 6- and 12-month risk-adjusted price momentum calculations are then standardized at +/- 3 standard deviations and translated into an average momentum score. The weight of each Underlying Index constituent is determined by multiplying the security's momentum score by its market capitalization-weight in the Parent Index. Additionally, each individual issuer is capped at 5%. MSCI uses an algorithm to determine the number of components in the Underlying Index based on the number of constituents in the Parent Index. The number of components is evaluated semi-annually.