Actually, scratch that. It's almost certainly intended to be two words based on credits in the database. I guess the S/T in different sizes in the logo also signifies this.
https://vgmdb.net/album/33780
https://vgmdb.net/album/31379
https://vgmdb.net/album/38217
https://vgmdb.net/album/35792
https://vgmdb.net/album/29725
"Yasuhiro Tanaka (Soul Tag Label / Sony Music Direct (Japan) Inc.)"