| Baylor College of Medicine |
12,250 |
| Houston Community College |
3,907 |
| Shell Oil Company |
3,027 |
| ConocoPhillips Company |
2,040 |
| Rice University |
1,986 |
| The University of Texas M. D. Anderson Cancer Center |
1,837 |
| BMC Software, Inc. |
1,687 |
| Halliburton Company |
1,508 |
| SYSCO Corporation |
1,492 |
| Baker Hughes Incorporated |
1,401 |
| Schlumberger Limited |
1,339 |
| Fulbright |
1,330 |
| Waste Management, Inc. |
1,176 |
| Vinson & Elkins L.L.P. |
1,162 |
| Prudential Gary Greene Rltrs - Penny N. Pefanis |
1,123 |
| Baker Botts LLP |
1,028 |
| Marathon Oil Corporation |
959 |
| El Paso Corporation |
940 |
| University of Houston |
931 |
| Stewart Information Services Corporation |
890 |
| Continental Airlines, Inc. |
831 |
| City of Houston, Texas |
785 |
| Houston Independent School District |
771 |
| CenterPoint Energy, Inc. |
756 |
| National Oilwell Varco |
742 |
| Harris County, Texas |
712 |
| LyondellBasell |
709 |
| Andrews Kurth LLP |
691 |
| Cameron International Corporation |
674 |
| Atos Origin NA, Inc. |
605 |
| Transwestern Commercial Services |
589 |
| Kinder Morgan, Inc. |
582 |
| Tesco Corporation |
576 |
| COMSYS IT Partners, Inc. |
576 |
| University of Texas Health Science Center |
571 |
| Weatherford International Ltd. |
567 |
| VALIC |
549 |
| Cooper Industries Ltd. |
546 |
| Apache Corporation |
542 |
| Bracewell |
528 |
| Texas Children's Hospital |
515 |
| Invesco AIM |
513 |
| Memorial Hermann Healthcare System |
493 |
| CORESTAFF Services |
492 |
| Houston Chronicle |
486 |
| Reliant Energy |
465 |
| UH-Downtown |
459 |
| FMC Technologies, Inc. |
451 |
| Total SA |
440 |
| Smith International, Inc. |
413 |
| Aker Solutions |
411 |
| KBR, Inc. |
407 |
| CITGO Petroleum Corporation |
406 |
| Hines Interests L.P. |
399 |
| Harris County, Texas |
398 |
| BJ Services Company |
390 |
| Service Corporation International |
381 |
| EOG Resources, Inc. |
347 |
| Wood Group |
339 |
| Dynegy Inc. |
327 |
| Cyberonics, Inc. |
323 |
| St. Luke's Episcopal Health System |
320 |
| Saudi Aramco |
315 |
| Dresser-Rand Company |
308 |
| InterTek, Inc. |
301 |
| Exterran Holdings, Inc. |
296 |
| United Space Alliance, LLC |
284 |
| Transocean Inc. |
278 |
| WorleyParsons Corporation |
275 |
| American Bureau of Shipping (ABS) |
275 |
| Enterprise Products Partners L.P |
267 |
| Calpine Corporation |
267 |
| The Men's Wearhouse, Inc. |
264 |
| The Menninger Clinic |
263 |
| Heritage Texas Properties - Mary J. Steele |
263 |
| Spectra Energy Partners, L.P. |
261 |
| Noble Energy, Inc. |
251 |
| Crown Castle International Corp. |
250 |
| Key Energy Services Inc. |
249 |
| Newfield Exploration Company |
248 |
| Southern Union Company |
247 |
| Argus Financial Software |
244 |
| Integrated Electrical Services, Inc. |
242 |
| Oceaneering International, Inc. |
237 |
| Southwestern Energy Company |
225 |
| PM Realty Group Lp |
218 |
| John Daugherty Realtors |
218 |
| M-I SWACO |
217 |
| Core Laboratories |
216 |
| INX, Inc. |
216 |
| CEMEX USA, Inc. |
216 |
| NetIQ |
216 |
| Amegy Bank of Texas |
215 |
| Martha Turner Properties |
214 |
| Jiffy Lube International, Inc. |
213 |
| TietoEnator |
211 |
| Methodist Health Care System |
210 |
| Enron Creditors Recovery Corporation |
208 |
| CGGVeritas |
204 |
| CYPRESS-FAIRBANKS ISD |
204 |
| Stage Stores |
202 |
| Nabors Drilling USA, LP |
199 |
| Kirby Corporation |
197 |
| Metals USA Holdings Corp. |
189 |
| Republic National Distributing Company, Inc. |
188 |
| Pride International, Inc. |
184 |
| Plains All American Pipeline, L.P. |
182 |
| Texas Southern University |
182 |
| Next Financial Group |
182 |
| NATCO Group Inc. |
180 |
| Loomis, Fargo & Company |
178 |
| Champion Technologies, Inc. |
176 |
| Mustang Engineering, Inc. |
176 |
| IFCO Systems North America, Inc. |
171 |
| Helix Energy Solutions Group, Inc. |
169 |
| NetVersant Solutions, Inc |
165 |
| McDermott International, Inc. |
164 |
| Wilson |
161 |
| Spring Independent School District |
158 |
| HCC Insurance Holdings, Inc. |
158 |
| FreshPoint, Inc. |
156 |
| Greenwood-King Properties |
156 |
| Quanta Services, Inc. |
155 |
| Plains Exploration |
154 |
| Aldine Independent School District |
152 |
| Sasol North America Inc. |
151 |
| Westlake Chemical Corporation |
150 |
| Harris County Hospital District |
149 |
| H-GAC |
148 |
| WAIS MedClub |
148 |
| Rosetta Inc |
145 |
| Weingarten Realty Investors |
139 |
| Universal Weather and Aviation, Inc. |
138 |
| ION Geophysical Corporation |
138 |
| Stewart & Stevenson Services, Inc. |
134 |
| Sterling Bancshares, Inc. |
132 |
| Porter |
130 |
| National Oilwell Varco, Inc. |
128 |
| Tenaris |
125 |
| Foxconn Corporation |
124 |
| TEPPCO Partners, L.P. |
122 |
| Swift Energy Company |
122 |
| Houston Baptist University |
121 |
| Camden Property Trust |
120 |
| Goodman Global, Inc. |
119 |
| Powell Industries, Inc. |
118 |
| Caprock Communications Inc |
117 |
| Hilcorp Energy Company |
115 |
| Greater Houston Partnership |
114 |
| YMCA of Greater Houston |
112 |
| Aramco Services Company |
111 |
| KS Management Services |
109 |
| ABS Consulting, Risk Management |
109 |
| NCI Building Systems, Inc. |
108 |
| Cheniere Energy, Inc. |
108 |
| Port of Houston |
107 |
| Mitsubishi Caterpillar Forklift America, Inc. |
106 |
| Coats Rose Yale Ryman Lee |
106 |
| PROS Holdings, Inc. |
106 |
| Houston Community Newspapers |
105 |
| Cabot Oil & Gas Corporation |
104 |
| Chamberlain, Hrdlicka, White, Williams |
100 |
| Susman Godfrey L.L.P. |
100 |
| Rimkus Consulting Group |
98 |
| Region 4 Education Service Center |
98 |
| Consolidated Graphics, Inc. |
97 |
| Gowco Inc |
97 |
| Jardine Lloyd Thompson LLC |
96 |
| Beirne, Maynard, |
95 |
| Aggreko USA LLC |
95 |
| SUEZ Energy North America, Inc. |
93 |
| Cornell Companies, Inc. |
93 |
| Houston Association of Realtors |
92 |
| CMAI- Chemical Market Associates, Inc. |
91 |
| The Planet.Com Internet Services, Inc. |
91 |
| David Weekley Homes (US Headquarters) |
90 |
| Merichem Company |
89 |
| Philip Services Corporation (PSC) |
89 |
| Victory Packaging, Inc. |
88 |
| University of Houston - Clear Lake |
88 |
| University of St. Thomas - Houston |
87 |
| Signature Hospital |
87 |
| Vopak Terminals North America Inc |
85 |
| Oil States International, Inc. |
84 |
| CARBO Ceramics Inc. |
83 |
| VeriCenter, Inc. |
83 |
| Allied Home Mortgage Capital Corporation |
83 |
| P2 Energy Solutions Inc. |
82 |
| The Panhandle Pipe Line Company |
81 |
| e-realty |
80 |
| Walter P. Moore and Associates, Inc. |
80 |
| GC Services Limited Partnership |
80 |
| Group 1 Automotive, Inc. |
79 |
| Equaterra |
79 |
| Logix Communications |
78 |
| Metropolitan Transit Authority of Harris County, Texas |
78 |
| Landry's Restaurants, Inc. |
77 |
| Willbros Group |
75 |
| Petrobras-USA |
75 |
| Riviana Foods Inc. |
74 |
