| 8 | U SAVE | 414 | 497 | |
| 9 | UGLY DUCKLING | 51 | 61 | |
| 6 | U-HAUL | 12399 | 14879 | |
| 6 | U-HAUL | 10322 | 12386 | |
| 506370 | ULTRASONIC EQUIPMENT & SUPPLIES (WHOL) | 202 | 242 | |
| 873441 | ULTRASONIC INSPECTION SERVICE | 15 | 18 | |
| 809954 | ULTRASOUND IMAGING-MEDICAL | 35 | 42 | |
| 504729 | ULTRAVIOLET RAY LAMPS & APPARATUS (WHOL) | 55 | 66 | |
| 569918 | UMBRELLAS | 95 | 114 | |
| 399954 | UMBRELLAS-MANUFACTURERS | 24 | 29 | |
| 513627 | UMBRELLAS-SUPPLIES (WHOLESALE) | 2 | 2 | |
| 513617 | UMBRELLAS-WHOLESALE | 27 | 32 | |
| 2674 | UNCOATED PAPER & MULTIWALL BAGS | 927 | 1112 | |
| B | UNDERGARMENTS | 6 | 7 | |
| B | UNDERGARMENTS | 1 | 1 | |
| 162310 | UNDERGROUND WIRE & CABLE LAYING CONTRS | 176 | 211 | |
| U | UNDERWEAR | 6 | 7 | |
| 225401 | UNDERWEAR (MANUFACTURERS) | 49 | 59 | |
| 224107 | UNDERWEAR TRIMMINGS (MANUFACTURERS) | 4 | 5 | |
| 564114 | UNDERWEAR-CHILDREN'S | 10 | 12 | |
| 232201 | UNDERWEAR-MENS-MANUFACTURERS | 25 | 30 | |
| 513618 | UNDERWEAR-MENS-WHOLESALE | 11 | 13 | |
| 513612 | UNDERWEAR-WHOLESALE | 233 | 280 | |
| 874869 | UNEMPLOYMENT INSURANCE CONSULTANTS | 36 | 43 | |
| 7 | UNI MARTS INC | 345 | 414 | |
| 7 | UNI MARTS INC | 224 | 269 | |
| 221112 | UNIFORM FABRICS (MANUFACTURERS) | 3 | 4 | |
| 721803 | UNIFORM RENTAL SERVICE | 297 | 356 | |
| 569921 | UNIFORM SUPPLY SERVICE | 1716 | 2059 | |
| 569922 | UNIFORMS | 5228 | 6274 | |
| 569920 | UNIFORMS-ACCESSORIES | 200 | 240 | |
| 513745 | UNIFORMS-ACCESSORIES-WHOLESALE | 2 | 2 | |
| 232604 | UNIFORMS-MANUFACTURERS | 85 | 102 | |
| 513701 | UNIFORMS-MEN'S & WOMEN'S-WHOLESALE | 244 | 293 | |
| 491102 | UNINTERRUPTIBLE POWER SYSTEMS | 79 | 95 | |
| 863102 | UNIONS-INDUSTRIAL | 71 | 85 | |
| 9 | UNIROYAL | 3441 | 4129 | |
| 6726 | UNIT INVESTMENT TRUSTS | 1571 | 1885 | |
| 672699 | UNIT INVESTMENT TRUSTS-CERTIFICATE OFCS | 62 | 74 | |
| 8 | UNITED | 504 | 605 | |
| 43 | UNITED STATES POSTAL SERVICE | 31362 | 37634 | |
| 4311 | UNITED STATES POSTAL SERVICE | 31362 | 37634 | |
| 501506 | UNIVERSAL JOINTS (WHOLESALE) | 106 | 127 | |
| U | UNKNOWN DEGREE | 631 | 757 | |
| U | UNKNOWN DEGREE | 1617 | 1940 | |
| Z | UNOCAL | 2171 | 2605 | |
| 3081 | UNSUPPORTED PLASTICS FILM & SHEET | 1362 | 1634 | |
| 3082 | UNSUPPORTED PLASTICS PROFILE SHAPES | 583 | 700 | |
| 308198 | UNSUPPORTED PLASTICS-FILM/SHEET (MFRS) | 531 | 637 | |
| 764109 | UPHOLSTERERS | 20076 | 24091 | |
| 508741 | UPHOLSTERERS SUPPLIES (WHOLESALE) | 695 | 834 | |
| 229905 | UPHOLSTERERS SUPPLIES-MANUFACTURERS | 96 | 115 | |
| 508762 | UPHOLSTERERS-WHOLESALE | 1 | 1 | |
| 508782 | UPHOLSTERY CLEANING EQUIP/SUPLS (WHOL) | 2 | 2 | |
| 571408 | UPHOLSTERY FABRICS-RETAIL | 1721 | 2065 | |
| 513109 | UPHOLSTERY FABRICS-WHOLESALE | 558 | 670 | |
| 109401 | URANIUM | 24 | 29 | |
| 108103 | URANIUM EXPLORATION | 1 | 1 | |
| 1094 | URANIUM RADIUM VANADIUM ORES | 46 | 55 | |
| 109498 | URANIUM RADIUM VANADIUM ORES | 23 | 28 | |
| 282202 | URETHANE & URETHANE PRODUCTS-MFRS | 22 | 26 | |
| 5 | UROLOGY | 5654 | 6785 | |
| 5932 | USED MERCHANDISE STORES | 95459 | 114551 | |
| 3 | USF&G | 3 | 4 | |
| 3 | USF&G | 2 | 2 | |
| 3 | USF&G | 884 | 1061 | |
| 736307 | USHER SERVICE | 11 | 13 | |
| 493902 | UTILITIES | 227 | 272 | |
| 671904 | UTILITIES-HOLDING COMPANIES | 47 | 56 | |
| 493903 | UTILITIES-UNDERGROUND-CABLE LOCATING SVC | 365 | 438 | |
| 506310 | UTILITIES-UNDRGRND-CBL PIPE/WIRE (WHOL) | 23 | 28 | |
| 874255 | UTILITY BILL CONSULTANTS | 23 | 28 | |
| 162308 | UTILITY CONTRACTORS | 2156 | 2587 | |
| 493904 | UTILITY MANAGEMENT | 39 | 47 | |
| 7519 | UTILITY TRAILER RENTAL | 15194 | 18233 |