http://finra.complinet.com/en/display/display_main.html?rbid=2403&element_id=9338 (a) No member shall display, rank, or accept a bid or offer, an order, or an indication of interest in any OTC Equity Security priced in an increment smaller than $0.01 if that bid or offer, order or indication of interest is priced equal to or greater than $1.00 per share. (b) No member shall display, rank, or accept a bid or offer, an order, or an indication of interest in any OTC Equity Security priced in an increment smaller than $0.0001 if that bid or offer, order or indication of interest is priced less than $1.00 per share except, where an order or indication of interest is priced less than $0.0001, a member may rank or accept (but not display) such order or indication of interest in an increment of $0.000001 or greater.