(a) At any time following conclusion of the rebuttal period specified in 17 CFR 201.700(c)(3)(i), the Commission may issue an order approving or disapproving the self-regulatory organization's proposed rule change together with a written statement of the reasons therefor.

(b) At any time following conclusion of the rebuttal period specified in 17 CFR 201.700(c)(3)(ii), the Commission may issue an order approving or disapproving the proposed national market system plan or proposed amendment to an effective national market system plan together with a written statement of the reasons therefor.