12 CFR §249.10

1. (a)Minimum liquidity coverage ratio requirement. Subject to the transition provisions in subpart F of this part, a Board-regulated institution must calculate and maintain a liquidity coverage ratio that is equal to or greater than 1.0 on each business day (or, in the case of a Category IV Board-regulated institution, on the last business day of the applicable month) in accordance with this part. A Board-regulated institution must calculate its liquidity coverage ratio as of the same time on each calculation date (the elected calculation time). The Board-regulated institution must select this time by written notice to the Board prior to December 31, 2019. The Board-regulated institution may not thereafter change its elected calculation time without prior written approval from the Board.
2. (b)Transition from monthly calculation to daily calculation. A Board-regulated institution that was a Category IV Board-regulated institution immediately prior to moving to a different category must begin calculating and maintaining a liquidity coverage ratio each business day beginning on the first day of the fifth quarter after becoming a Category I Board-regulated institution, Category II Board-regulated institution, or Category III Board-regulated institution.
3. (c)Calculation of the liquidity coverage ratio. A Board-regulated institution's liquidity coverage ratio equals:
   1. (1)The Board-regulated institution's HQLA amount as of the calculation date, calculated under subpart C of this part; divided by
   2. (2)The Board-regulated institution's total net cash outflow amount as of the calculation date, calculated under subpart D of this part.