Sohma Building

The Sohma Building is a buissness building in which the CEO is Momiji's Father.

Overview
From the beginning of the series, Tohru Honda and several older ladies have been working as cleaning ladies of the building. Since his father is the president of the building, Momiji Sohma often goes there to play and helps Tohru out. It is also mentioned that Momiji's Mother and Momo Sohma often visits the building to pick Momiji's father up and go home together.

Apparently, even though the building is Sohma-owned and the CEO of the building is a Sohma, the name of the company isn't Sohma, which is why neither Tohru or Yuki Sohma realized that it was Sohma-owned.