The iMoneyNet rate is an average net rate of all the larger 2A7 government money market funds. The LGIP is molded after a 2A7 fund. These funds all have weighted average maturities of less than 60 days, and may only invest in securities with maturities no longer than 397 days.
The Office of the State Treasurer (OST) manages the Local Government Investment Pool (LGIP) on behalf of more than 500 taxing bodies within Washington state. Putting short-term surplus cash into LGIP, with 100 percent liquidity, allows local governments the ability to earn better interest on these funds than they likely would, otherwise.