Mark Catlin admitted Pompey are trying to reach a ‘basket case’ Championship.
And the chief executive promised the Blues will not copy ‘ego-driven’ owners plugging huge debts at second-tier outfits.
The most recently available accounts of clubs underline the extreme financial pressure being placed on clubs.
A total of 12 clubs have wage bills which are more than their incomes – with Birmingham paying double what they brought in.
Catlin underlined Pompey will not repeat the scenario.
He said: ‘The Championship is a basket case.
‘You have a mix of clubs coming down with £40m parachute payments.
‘To compete with that, you've then got a group of clubs quite happy to lose £40m to compete with those coming down.
‘It's the biggest contradiction of terms is “why don't X club invest in League One to get into the Championship?”
‘It's not an investment. It's the only business in the world where you're investing to lose more money - that's a contradiction.
‘An investment is to put something in to get more out.
‘A lot of owners are ego-driven. It's for their own ego they want to drive success and they are prepared to put the club at risk in trying to do that – we are not.’
Catlin highlighted how a benefactor pulling the plug on clubs operating with large debts will send them over the precipice.
It’s a scenario, of course, witnessed at Fratton Park in the past.
Catlin added ‘It's sustainable as long as people are willing to lose that level of money.
‘It becomes unsustainable when an owner say “I've had enough” and then the club is very exposed.’