A press release, "Moody's assigns Aaa-mf rating to Aviva Investors USD Liquidity Fund" explains, "Moody's Investors Service has assigned a Aaa-mf to Aviva Investors USD Liquidity Fund (the "Fund"), a Low Volatility Net Asset Value (LVNAV) money market fund, domiciled in Ireland and managed by Aviva Investors Luxembourg S.A. (Aviva Investors). The Fund's primary investment objective is to achieve a return in line with money market rates while preserving capital and providing daily liquidity." The release continues, "The Aaa-mf rating reflects Moody's view that the Fund will have a very strong ability to meet its objectives of providing liquidity and preserving capital. This view is supported by the model portfolio's high scores for each of the key rating factors, including credit quality, asset profile, liquidity and exposure to market risk. The Fund intends to invest in high credit quality securities, primarily short-dated commercial paper and deposit securities as well as short-dated bonds from government, agency, corporate and financial issuers. The Fund's weighted average maturity (WAM) is expected to be below 60 days and we expect the Fund to maintain a strong liquidity profile supported by high levels of overnight and weekly liquidity in the portfolio. As a result, we expect the Fund to have a low exposure to market risk. During the ramp-up period, Moody's expects that the Fund will have some shareholder concentration risk, that is expected to decrease within 6 months as the Fund grows and its shareholder base diversifies. The rating agency expects the Fund to be managed in line with the model portfolio. However, Moody's notes that if the Fund's investment portfolio was to deviate materially from the model portfolio and its shareholder base remains concentrated, the Fund's rating could be changed. Aviva Investors is an investment asset manager with GBP356 billion assets under management as of end of December 2019." See to: "Fitch Rates Aviva US Dollar Liquidity Fund 'AAAmmf'."