The club revealed this week that they lost £20m as they slumped out of the Premiership last season and have debts of £36m.
Reid was handed much of the blame because of “unacceptable” transfer deals he pushed through before being sacked 13 months ago.
He was given £18m to strengthen his squad at the start of last season, taking Sunderland £40m into the red.
Reid bought Tore Andre Flo, Marcus Stewart, Stephen Wright and Matt Piper as well as securing lucrative contracts to free transfer signings Phil Babb and Thomas Myhre.
But plc chairman Bryan Sanderson also admitted that the decision to replace him with Howard Wilkinson was a big mistake too.
He said: “Our relegation was not a surprise following the inadequate performance on the field throughout the season.
“The management of the team and of the acquisitions in the transfer market was unacceptable.