On March 23rd, the SEC provided notice of NYSE Arca's proposal to amend the bid-ask differentials for Market Maker quotations outlined in Rule 6.37A(b)(4), and amending Rule 6.64(b) by establishing guidelines for the use of bid-ask parameters in the OX System to be used during the opening auction process. Comments should be submitted within 21 days after publication in the Federal Register, which is expected during the week of March 29. SEC Release No. 34-61759.