The index had started last week down, dropping gradually, central bank data show.
The index returned to less than 7% early in July, for the first time in two months. The three-month ROBOR jumped from 6.47% to 7.25% on May 8.
The six-month ROBOR, used to calculate variable interest rates for mortgage loans in lei, fell to 6.82% on July 21 from 6.83% on July 18.
The 12-month ROBOR dropped to 6.95% from 6.96% on Friday.
(English version by Loredana Fratila-Cristescu)