I've noticed a few strange things going on with some stocks, in that they are sometimes quoted to 3 or 4 decimal places even though they trade in pennies. For example, on 6/23 here's a few data points that seem strange: NYSE:NFG: Open: 58.045 NYSEAI: Open: 67.5514 AMEXBE: High 17.564 NYSE:CCK: High: 27.5575 AMEX:XLB: Low: 43.1801 AMEX:XLV: Low: 30.209 NASDAQ:IFGL: Close: 38.821 NASDAQ:NGA: Close: 8.852 NYSE: F (PR S): Close: 29.765 It seems that most web sites (yahoo, google finance etc.) round or truncate this date to two decimal places though... It's different securities every day that exhibit this issue, so doesn't seem limited to certain securities. Can anyone explain how/why these securities are trading at different increments to the rest of the market?