| Code | Name | High | Low | Close | Volume | Change |
| OABC | OmniAmerican Bancorp Inc. | 11.30 | 11.15 | 11.19 | 9,220 | 0.09 |  | 0.81 |
| OBAF | OBA Financial Services Inc. | 11.02 | 11.02 | 11.02 | 5,000 | 0.00 |  | 0.00 |
| OBAS | Optibase Ltd. | 1.340 | 1.340 | 1.340 | 295 | 0.010 |  | 0.75 |
| OBCI | Ocean Bio-Chem Inc. | 1.680 | 1.600 | 1.630 | 6,516 | 0.020 |  | 1.21 |
| OCCF | Optical Cable Corporation | 2.320 | 2.250 | 2.250 | 3,400 | 0.100 |  | 4.26 |
| OCFC | OceanFirst Financial Corp. | 11.54 | 11.30 | 11.50 | 31,201 | 0.18 |  | 1.59 |
| OCLR | Oclaro Inc. | 12.86 | 12.44 | 12.52 | 958,839 | 0.07 |  | 0.56 |
| OCLS | Oculus Innovative Sciences Inc. | 1.690 | 1.600 | 1.600 | 30,985 | 0.060 |  | 3.61 |
| OCNF | OceanFreight Inc. | 0.9600 | 0.9200 | 0.9387 | 144,808 | 0.0100 |  | 1.08 |
| OCNW | Occam Networks Inc. | 4.660 | 4.370 | 4.420 | 93,777 | 0.070 |  | 1.56 |
| OCZ | OCZ Technology Group Inc | 2.350 | 1.960 | 2.250 | 54,976 | 0.270 |  | 13.64 |
| ODFL | Old Dominion Freight Line Inc. | 25.79 | 24.99 | 25.47 | 340,028 | 0.61 |  | 2.45 |
| ODSY | Odyssey Healthcare Inc. | 27.01 | 26.99 | 27.01 | 1,406,443 | 0.05 |  | 0.19 |
| OFIX | Orthofix International N.V. | 28.88 | 28.20 | 28.84 | 180,454 | 0.63 |  | 2.23 |
| OFLX | Omega Flex Inc. | 13.14 | 12.99 | 13.14 | 554 | 0.15 |  | 1.15 |
| OGXI | OncoGenex Pharmaceuticals Inc. | 13.08 | 12.75 | 12.80 | 8,621 | 0.13 |  | 1.01 |
| OICO | O. I. Corporation | 8.000 | 7.810 | 7.810 | 4,109 | 0.100 |  | 1.26 |
| OIIM | O2Micro International Limited | 6.150 | 5.990 | 6.010 | 106,681 | 0.040 |  | 0.66 |
| OINK | Tianli Agritech Inc. | 3.800 | 3.750 | 3.790 | 6,300 | 0.020 |  | 0.52 |
| OKSB | Southwest Bancorp Inc. | 11.99 | 11.60 | 11.60 | 114,417 | 0.37 |  | 3.09 |
| OKSBP | Southwest Bancorp Inc. | 27.40 | 27.00 | 27.00 | 1,800 | 0.26 |  | 0.97 |
| OLBK | Old Line Bancshares Inc. | 7.890 | 7.820 | 7.880 | 1,186 | 0.340 |  | 4.51 |
| OLCB | Ohio Legacy Corporation | 2.050 | 2.040 | 2.050 | 928 | 0.100 |  | 5.13 |
| OMAB | Grupo Aeroportuario del Centro Norte | 11.75 | 11.51 | 11.59 | 16,296 | 0.13 |  | 1.11 |
| OMCL | Omnicell Inc. | 11.72 | 11.48 | 11.53 | 78,521 | 0.08 |  | 0.70 |
| OMER | Omeros Corporation | 6.389 | 6.080 | 6.280 | 34,217 | 0.160 |  | 2.61 |
| OMEX | Odyssey Marine Exploration Inc. | 1.650 | 1.590 | 1.650 | 165,256 | 0.020 |  | 1.23 |
| OMNI | OMNI Energy Services Corp. | 2.730 | 2.710 | 2.730 | 56,493 | 0.020 |  | 0.74 |
| OMPI | Obagi Medical Products Inc. | 10.55 | 10.13 | 10.21 | 116,312 | 0.28 |  | 2.67 |
| ONAV | Omega Navigation Enterprises Inc. | 1.440 | 1.400 | 1.400 | 52,390 | 0.020 |  | 1.45 |
| ONCY | Oncolytics Biotech Inc. | 3.420 | 3.280 | 3.400 | 126,419 | 0.130 |  | 3.98 |
| ONEQ | Fidelity Nasdaq Composite Index Tracking | 88.02 | 87.47 | 87.81 | 11,121 | 0.72 |  | 0.83 |
| ONFC | Oneida Financial Corp. | 7.800 | 7.650 | 7.700 | 7,311 | 0.150 |  | 1.99 |
| ONNN | ON Semiconductor Corporation | 6.430 | 6.190 | 6.390 | 7,910,090 | 0.060 |  | 0.95 |
| ONSM | Onstream Media Corporation | 1.040 | 0.940 | 1.030 | 12,649 | 0.020 |  | 1.98 |
| ONTY | Oncothyreon Inc . | 3.550 | 3.450 | 3.530 | 36,868 | 0.020 |  | 0.56 |
| ONVI | Onvia Inc. | 3.000 | 2.880 | 3.000 | 1,380 | 0.050 |  | 1.64 |
| ONXX | ONYX Pharmaceuticals Inc. | 25.81 | 24.94 | 25.75 | 1,234,848 | 0.48 |  | 1.90 |
| OPEN | OpenTable Inc. | 56.48 | 54.92 | 55.50 | 175,175 | 0.69 |  | 1.26 |
| OPHC | OptimumBank Holdings Inc. | 0.5000 | 0.5000 | 0.5000 | 1,000 | 0.0000 |  | 0.00 |
| OPLK | Oplink Communications Inc. | 17.69 | 16.95 | 17.23 | 116,877 | 0.13 |  | 0.76 |
| OPNT | OPNET Technologies Inc. | 16.83 | 16.40 | 16.67 | 63,649 | 0.27 |  | 1.65 |
| OPOF | Old Point Financial Corporation | 12.05 | 11.81 | 11.92 | 1,200 | 0.08 |  | 0.68 |
| OPTC | Optelecom-NKF Inc. | 1.400 | 1.398 | 1.398 | 200 | 0.010 |  | 0.72 |
| OPTR | Optimer Pharmaceuticals Inc. | 8.120 | 8.000 | 8.030 | 183,473 | 0.070 |  | 0.88 |
| OPTT | Ocean Power Technologies Inc. | 5.050 | 4.780 | 4.820 | 49,464 | 0.130 |  | 2.63 |
| OPWV | Openwave Systems Inc | 1.700 | 1.630 | 1.650 | 161,241 | 0.010 |  | 0.60 |
| OPXA | Opexa Therapeutics Inc. | 1.130 | 1.050 | 1.090 | 54,750 | 0.000 |  | 0.00 |
| OPXAW | Opexa Therapeutics Inc. | 0.6100 | 0.5900 | 0.6100 | 4,082 | 0.0200 |  | 3.33 |
| OPXT | Opnext Inc. | 1.470 | 1.420 | 1.440 | 170,506 | 0.010 |  | 0.70 |
| ORBC | ORBCOMM Inc. | 2.020 | 1.950 | 2.000 | 50,985 | 0.010 |  | 0.50 |
| ORBK | Orbotech Ltd. | 10.15 | 10.00 | 10.07 | 20,509 | 0.03 |  | 0.30 |
| ORBT | Orbit International Corporation | 3.480 | 3.280 | 3.480 | 2,325 | 0.010 |  | 0.29 |
| ORCC | Online Resources Corporation | 4.060 | 3.940 | 4.050 | 102,397 | 0.070 |  | 1.76 |
| ORCH | Orchid Cellmark Inc. | 1.450 | 1.380 | 1.430 | 4,732 | 0.060 |  | 4.38 |
| ORCL | Oracle Corporation | 24.23 | 23.88 | 24.14 | 54,699,581 | 0.12 |  | 0.49 |
| ORCT | Orckit Communications Limited | 2.380 | 2.330 | 2.350 | 7,940 | 0.020 |  | 0.84 |
| OREX | Orexigen Therapeutics Inc. | 5.390 | 5.220 | 5.320 | 758,410 | 0.030 |  | 0.57 |
| ORIT | Oritani Financial Corp. | 9.870 | 9.700 | 9.840 | 334,983 | 0.200 |  | 2.07 |
| ORLY | O'Reilly Automotive Inc. | 50.29 | 49.55 | 50.26 | 954,575 | 0.68 |  | 1.37 |
| ORRF | Orrstown Financial Services Inc | 22.19 | 21.50 | 21.66 | 4,267 | 0.16 |  | 0.74 |
| OSBC | Old Second Bancorp Inc. | 0.8500 | 0.7340 | 0.7953 | 376,356 | 0.0200 |  | 2.44 |
| OSBCP | Old Second Bancorp Inc. | 2.390 | 2.200 | 2.390 | 11,241 | 0.010 |  | 0.42 |
| OSHC | Ocean Shore Holding Co. | 10.55 | 10.54 | 10.55 | 300 | 0.01 |  | 0.09 |
| OSIR | Osiris Therapeutics Inc. | 6.770 | 6.610 | 6.670 | 45,233 | 0.040 |  | 0.60 |
| OSIS | OSI Systems Inc. | 31.98 | 31.31 | 31.90 | 143,613 | 0.58 |  | 1.85 |
| OSTE | Osteotech Inc. | 6.400 | 6.390 | 6.390 | 603,680 | 0.020 |  | 0.31 |
| OSTK | Overstock.com Inc. | 15.14 | 14.56 | 14.64 | 85,782 | 0.01 |  | 0.07 |
| OSUR | OraSure Technologies Inc. | 3.470 | 3.320 | 3.360 | 85,396 | 0.020 |  | 0.59 |
| OTEX | Open Text Corporation | 44.99 | 44.46 | 44.70 | 364,978 | 0.29 |  | 0.65 |
| OTIV | On Track Innovations Ltd | 1.810 | 1.710 | 1.800 | 72,949 | 0.000 |  | 0.00 |
| OTIX | OTIX Global Inc | 4.130 | 4.050 | 4.050 | 27,971 | 0.000 |  | 0.00 |
| OTT | Otelco Inc. | 15.93 | 15.70 | 15.78 | 52,746 | 0.06 |  | 0.38 |
| OTTR | Otter Tail Corporation | 19.48 | 19.13 | 19.18 | 142,460 | 0.01 |  | 0.05 |
| OUTD | Outdoor Channel Holdings Inc. | 5.490 | 5.260 | 5.410 | 20,204 | 0.150 |  | 2.85 |
| OVBC | Ohio Valley Banc Corp. | 19.70 | 19.20 | 19.20 | 200 | 0.06 |  | 0.31 |
| OVLY | Oak Valley Bancorp (CA) | 5.490 | 5.020 | 5.080 | 1,813 | 0.150 |  | 2.87 |
| OVRL | Overland Storage Inc. | 1.640 | 1.640 | 1.640 | 100 | 0.020 |  | 1.23 |
| OVTI | OmniVision Technologies Inc. | 21.30 | 20.04 | 20.08 | 2,822,214 | 0.92 |  | 4.38 |
| OXBT | Oxygen Biotherapeutics Inc. | 2.960 | 2.840 | 2.850 | 19,383 | 0.040 |  | 1.42 |
| OXGN | OXiGENE Inc. | 0.3090 | 0.2800 | 0.2801 | 1,789,189 | 0.0200 |  | 6.67 |
| OXPS | optionsXpress Holdings Inc. | 15.07 | 14.89 | 15.02 | 87,308 | 0.20 |  | 1.35 |
| OYOG | OYO Geospace Corporation | 49.99 | 48.75 | 49.61 | 35,480 | 1.25 |  | 2.58 |
| OZRK | Bank of the Ozarks | 37.20 | 36.61 | 36.87 | 54,682 | 0.02 |  | 0.05 |