Carson Yeung this week celebrates one year in charge at St Andrew's, during which time he has rebuilt the playing staff, adding the likes of Alexander Hleb, Ben Foster and Nikola Zigic to the payroll.
But vice-chairman Pannu has warned fans not to expect the spending to continue unchecked.
"Carson wants to build the club but he is also equally mindful of the pitfalls of improving at a pace that could cause problems for the club," Pannu told the Birmingham Mail.
"It has to be done at a more sustainable level, step by step. The fans wish to see improvements on the pitch but how you achieve that is important.
"Blindly demanding the owners pump in money to secure established players is equivalent to a wife saying 'if you don't do this and that on credit, then I will leave you'.
"I think none of our fans would do that but will try to satisfy the wife in a different way or call it quits. In the context of a financial household situation, running a football club is no different."