Md. Code, Insurance § 11–209

(a) (1) Notwithstanding any other provision of this subtitle, an insurer may reduce its rates previously approved by the Commissioner by filing the reduced rates with the Commissioner within 30 days after the reduced rates become effective.

(2) An insurer that has reduced its rates in accordance with paragraph (1) of this subsection may withdraw the reduction wholly or partly by filing revised rates at a level not higher than the level approved by the Commissioner before the reduction within 30 days after they become effective.

(b) If, after notice and a hearing, the Commissioner finds that the rates produced are in violation of this subtitle, the Commissioner may revoke a reduction of rates made in accordance with this section.