| 1 | NSP | Novosibirsk Aircraft Repair Plant, Joint-Stock Company | Callsign: Narpair, | RUS | AVCODES |
| 2 | NSP | Samaritans Purse | Callsign: Sam Purse, | USA | AVCODES |
| 3 | NSP | Novosibirsk Aircraft Repairing Plant | | | ICAO1 |
| 4 | NSP | NORTHERN STATES POWER COMPANY | | | PWRC |
| 5 | NSPA | NOBLE SHIPPING PVT LTD | | | SCAC4 |
| 6 | NSPD | NORTH STAR PRODUCE | | | SCAC4 |
| 7 | NSPE | NELSON PETROLEUM | | | SCAC4 |
| 8 | NSPG | NESTA SHIPPING V O F | | | SCAC4 |
| 9 | NSPH | NADEAUS PLUMBING & HEATING INC | | | SCAC4 |
| 10 | NSPT | NON-STOP TRANSPORT INC | | | SCAC4 |
| 11 | NSPX | Xcel Energy | added 1/2006 | | NAKINA |
| 12 | NSPX | Northern States Power Co. | added 7/1990; 1/1994-7/2000; eliminated 1/2003; added 4/2005; 7/2005; eliminated 1/2006 | | NAKINA |
| 13 | NSPX | Northern States Power Co. | added 7/90; 1/94-7/2000 | | NRHS |
| 14 | NSPX | XCEL ENERGY [NORTHERN STATES POWER COMPANY] | | | PWRC |
| 15 | NSPX | Northern States Power | | | RSRV |
| 16 | NSPX | XCEL ENERGY | | | SCAC4 |
| 17 | NSPZ | NORTHERN STATES POWER COMPANY | | | PWRC |
| 18 | NSPZ | NORFOLK SOUTHERN RAILWAY | | | PWRC |
| 19 | NSPZ | Norfolk Southern Railway | | | RSRV |
| 20 | NSPZ | NORFOLK SOUTHERN RAILWAY COMPANY (N | | | SCAC4 |
