| # | Company name | Role | # of Projects |
|---|---|---|---|
| 1 | abc | undefined | 0 |
| 2 | Across Corporation | developer | 7 |
| 3 | Aioi Insurance | developer | 3 |
| 4 | ANA Hotels Company Limited | tenant | 15 |
| 5 | Ando Corporation | construction company | 15 |
| 6 | Ando-Shoten Co., Ltd. | owner | 1 |
| 7 | Aoki Asunaro Construction Corporation | construction company | 2 |
| 8 | Aoshima Architects and Engineers | architect | 1 |
| 9 | Aqua City Corporation | owner | 1 |
| 10 | Arata Isozaki & Associates | architect | 16 |
| 11 | Arcs Corporation | developer | 1 |
| 12 | Art Housing Corporation | construction company | 0 |
| 13 | Arup Japan | structural engineering | 3 |
| 14 | Asahi Glass Co., Ltd. | glass supplier | 2 |
| 15 | Asahi Kasei Fudosan | property management | 1 |
| 16 | Asahi Kasei Homes | developer | 1 |
| 17 | Asahi Shimbun | owner | 2 |
| 18 | Ascot Community | property management | 1 |
| 19 | Ascot Corporation | general contractor | 7 |
| 20 | Ashihara Kenchiku Sekkei | architect | 1 |