| National Oilwell Varco Inc. |
12,699 |
| CYPRESS-FAIRBANKS Independent School Dist |
9,393 |
| Baylor College of Medicine |
8,580 |
| Shell Oil Company |
5,131 |
| Houston Community College |
4,511 |
| MD Anderson Cancer Center |
3,579 |
| Waste Management, Inc. |
3,283 |
| University of Houston |
3,128 |
| SYSCO Corporation |
3,095 |
| BMC Software Inc. |
3,019 |
| Baker Hughes Incorporated |
2,832 |
| Memorial Hermann Healthcare System |
2,782 |
| Weatherford International Ltd. |
2,778 |
| KBR, Inc. |
2,596 |
| Halliburton Company |
2,573 |
| Schlumberger Limited |
2,562 |
| Kinder Morgan, Inc. |
2,483 |
| Invensys Operations Management |
2,473 |
| University of Texas Health Science Center |
2,471 |
| ConocoPhillips |
2,011 |
| Tesco Corporation |
1,981 |
| American General Life Companies |
1,779 |
| American Air Liquide Holdings, Inc. |
1,724 |
| Rice University |
1,632 |
| CenterPoint Energy, Inc. |
1,593 |
| Texas Southern University |
1,424 |
| Total Petrochemicals USA, Inc. |
1,408 |
| The Methodist Hospital System |
1,324 |
| Houston Independent School District |
1,300 |
| City of Houston, Texas |
1,223 |
| UniversalPegasus International |
1,221 |
| Cameron International Corporation |
1,211 |
| University of Houston - Clear Lake |
1,028 |
| Transwestern |
1,010 |
| LyondellBasell |
999 |
| St. Luke's Episcopal Health System |
978 |
| UH-Downtown |
977 |
| FMC Technologies, Inc. |
968 |
| Stewart Information Services Corporation |
966 |
| Continental Airlines, Inc. |
959 |
| Vinson & Elkins L.L.P. |
920 |
| Kelsey-Seybold Clinic |
913 |
| Cemex |
833 |
| Cooper Industries plc |
832 |
| Baker Botts |
810 |
| Hines |
698 |
| Calpine Corporation |
687 |
| Southern Union Company |
672 |
| Service Corporation International (SCI) |
652 |
| Apache Corporation |
631 |
| Harris Health System |
617 |
| Veolia Water North America |
611 |
| Harris County, Texas |
607 |
| Reliant Energy Retail Holdings, LLC |
575 |
| Dresser-Rand Company |
559 |
| Prudential Gary Greene Realtors |
543 |
| Next Financial Group |
510 |
| EOG Resources, Inc. |
501 |
| Andrews Kurth LLP |
483 |
| Solvay Flourides LLC |
459 |
| Crown Castle International Corp. |
458 |
| Enterprise Products Partners L.P. |
457 |
| Harris County, Texas |
456 |
| Mustang Engineering |
452 |
| CITGO Petroleum Corporation |
450 |
| Marathon Oil Corporation |
436 |
| GDF SUEZ Energy North America, Inc. |
426 |
| Noble Energy, Inc. |
397 |
| Southwestern Energy Company |
396 |
| Spring Branch Independent School District |
389 |
| Loomis |
386 |
| Statoil |
385 |
| CGG Veritas |
379 |
| American Bureau of Shipping |
378 |
| Texas Children's Hospital |
378 |
| Oceaneering International, Inc. |
373 |
| Amegy Bank of Texas |
370 |
| Spectra Energy Partners, L.P. |
368 |
| Cyberonics, Inc. |
364 |
| Fugro Consultants Inc |
354 |
| Saudi Basic Industries Corporation Inc. |
348 |
| Core Laboratories |
348 |
| Cornerstone Mortgage |
342 |
| FreshPoint, Inc. |
339 |
| Tenaris Global Services (USA) Corp |
337 |
| McDermott International, Inc. |
332 |
| The Men's Wearhouse, Inc. |
332 |
| INX, Inc. |
324 |
| New Triumph Healthcare, Llp |
323 |
| United Space Alliance, LLC |
319 |
| Dynegy, Inc. |
313 |
| Nabors Industries |
310 |
| Saudi Aramco |
309 |
| Willbros Group |
293 |
| Wartsila North America |
290 |
| Exterran Holdings, Inc. |
284 |
| Kirby Corporation |
283 |
| Key Energy Services, Inc. |
281 |
| IFCO Systems North America, Inc. |
280 |
| MRC Global Inc. |
274 |
| Quanta Services, Inc. |
263 |
| Houston Chronicle |
262 |
| Port of Houston Authority |
261 |
| Westlake Chemical Corporation |
252 |
| Houston Baptist University |
249 |
| Epstein Becker & Green |
247 |
| Transocean Ltd. |
243 |
| Hill & Knowlton Inc. |
234 |
| M-I, L.L.C. |
229 |
| PM Realty Group Lp |
227 |
| Prosperity Bancshares, Inc. |
221 |
| Jardine Lloyd Thompson Group PLC |
221 |
| Region 4 Education Service Center |
220 |
| Targa Resources Inc. |
218 |
| Wilson |
218 |
| Phillips 66 |
217 |
| TietoEnator |
217 |
| Plains All American Pipeline, L.P. |
216 |
| Landry's Inc. |
215 |
| Universal Weather and Aviation, Inc. |
214 |
| PROS Holdings, Inc. |
210 |
| Foster Wheeler USA Corporation |
206 |
| Champion Technologies, Inc. |
205 |
| Oil States International, Inc. |
203 |
| Mitsubishi Caterpillar Forklift America, Inc. |
200 |
| ION Geophysical Corporation |
197 |
| Goodman Manufacturing |
193 |
| Buckeye Partners, L.P. |
193 |
| Houston Casualty Company |
192 |
| Camden Property Trust |
191 |
| Fuddruckers |
187 |
| Plains Exploration & Production |
186 |
| Stewart & Stevenson |
184 |
| Logix |
183 |
| Galena Park Independent School District |
182 |
| NetIQ |
177 |
| Kraton Performance Polymers, Inc. |
172 |
| Superior Energy Services, Inc. |
172 |
| Woodforest Financial Group, Inc. |
165 |
| Motiva Enterprises LLC |
165 |
| Rimkus Consulting Group |
164 |
| Boardwalk Pipeline Partners, LP |
164 |
| Porter Hedges LLP |
162 |
| Group 1 Automotive |
162 |
| Inspectorate America |
159 |
| EPCO, Inc. |
158 |
| ZIM AMERICAN ISRAELI SHIPPING |
158 |
| TAS Energy Inc. |
157 |
| Stage Stores Inc. |
152 |
| DXP Enterprises, Inc. |
151 |
| ABS Consulting, Risk Management.... |
150 |
| Enron Creditors Recovery Corporation |
149 |
| South Texas College Of Law |
148 |
| Weingarten Realty Investors |
148 |
| Victory Packaging, Inc. |
147 |
| Vopak |
143 |
| Alief Independent School District |
141 |
| YMCA of Greater Houston |
141 |
| Houston's First Baptist Church |
139 |
| University of St. Thomas - Houston |
138 |
| Powell Industries, Inc. |
138 |
| Spring Independent School District |
136 |
| Hilcorp Energy Company |
135 |
| PSC |
135 |
| Dubuis Health System |
134 |
| David Weekley Homes |
134 |
| Parker Drilling Company |
134 |
| Quanex Corporation |
131 |
| SBM Atlantia |
131 |
| Jiffy Lube Int'l. Inc. |
131 |
| Metropolitan Transit Authority of Harris County, Houston, Texas |
130 |
| CORESTAFF Services |
127 |
| Vitol, Inc. |
126 |
| HELIX Energy Solutions Group, Inc. |
125 |
| Wortham Insurance |
123 |
| GC Services Limited Partnership |
123 |
| Rowan Companies, Inc. |
122 |
| NCI Building Systems, Inc. |
121 |
| Heritage Texas Properties |
121 |
| ENGlobal Corporation |
120 |
| Petroleum Geo-Services |
120 |
| IES Commercial, Inc. |
118 |
| North Forest Independent School District |
118 |
| CMAI- Chemical Market Associates, Inc. |
117 |
| Equaterra, Inc. |
117 |
| NACE International |
116 |
| Carriage Services, Inc. |
116 |
| Neste Trading (USA.), Inc. |
115 |
| Texas Department of Transportation |
113 |
| Petrohawk Energy Corporation |
113 |
| Linn Energy, LLC. |
113 |
| Comfort Systems USA |
112 |
| Houstonian Hotel Club & Spa |
109 |
| Landmark Aviation |
109 |
| Greater Houston Partnership |
105 |
| Stress Engineering Services Inc. |
105 |
| Bracewell & Giuliani |
105 |
| Cudd Pressure Control, Inc. |
103 |
| NetVersant Solutions, Inc |
103 |
| Houston-Galveston Area Council |
103 |
