On January 14th, the SEC issued a concept release seeking public comment on market structure issues including high frequency trading, co-locating trading terminals, and markets that do not publicly display price quotations. Comments should be submitted within 90 days after publication in the Federal Register which is expected during the week of January 18. SEC Press Release. See also Schapiro Open Meeting Remarks; Paredes Open Meeting Remarks; Aguilar Open Meeting Remarks; Walter Open Meeting Remarks.