The club now hope to lease the offices out, enabling them to meet the rent on the stadium itself.
Joint-chairman Julian Rhodes said: "I'm not saying it solves everything but it means we will be able to stay at Valley Parade for next season."
He continued: "This move does help to ease all of our more pressing problems and means that we are saving the club a lot of money in the process."
Rhodes, his father and fellow shareholder Professor David Rhodes, and joint-chairman Mark Lawn have set up a parent company, BC Bantams limited, to buy the office block, which is owned by Prudential Property Investment Managers (PRUPIM).
The club were paying around ?700,000 a year in rent to PRUPIM and the pension fund of former chairman Gordon Gibb, the owners of Valley Parade.
Bradford City said last month that that figure was unsustainable for a League Two side, prompting plans of a move to Odsal, home of Super League side Bulls.
The club are still hoping to renegotiate the rent on the 25,000-capacity stadium, their home since 1903.
Following their relegation from the Premier League in 2001, the ground was sold to the pension fund of Gibb for around ?2.5m and subsequently rented back to the club.
Source: BBC Sport
Source: BBC Sport