Mark Catlin vowed there will be investment to allow Kenny Jackett to improve his Pompey squad this summer.
But the Blues chief executive is adamant the club will not compromise its future by pushing their financial limits to the extreme.
Catlin believes the questions being asked over the ambition of Pompey’s owners is not a reflection of the views of the majority of supporters or the board.
That’s after Jackett stated his playing budget will not change from the level it ended the last campaign at.
Catlin would not be drawn on the details of the war chest at his manager’s disposal, but sees leeway for the squad to continue its progress next term and flexibility in the budget.
He said: ‘Budgets should remain private.
‘It helps no one other than players’ agents and opposing clubs if it’s disclosed.
‘We don’t want to give people an advantage in any way
‘It (any signings) has to be within the general budget and players’ wages have to fit.
‘What you want is consistency - and that’s what we strive for.
‘What you don’t want is to be caught in an upward spiral.
‘We’ve seen that with clubs lately who you didn’t see getting into financial difficulties.
‘You can end up there. We know that from our own experience and we’re just never, ever going to allow that to happen.
‘We’ll never put the future of the club in jeopardy. When we move on a player it will be what we can afford within our operating P&L.
‘It doesn’t mean we stand still. We are still looking to progress as we have consistently over a number of years. That is a fact.
‘There will be investment but investments which bring money back into the club.
‘Then that money can be reinvested, whether that be player transfer fees, the playing budget or innovative business opportunities.
‘Our budget is very flexible, we may start off with ‘X’, but, as an example, through a combination of the strength of our commercial activities, and money generated through player ‘outs’, we end up with ‘Y’.
‘And above all of this, if the manager comes to us with a player he may want to sign outside of the agreed budget then we will of course listen to this sympathetically on a case-by-case basis.
‘The bottom line is the current playing budget is an irrelevance in the scheme of things, it’s just a rough snapshot of where we currently are at this moment in time.
‘That’s how our model works, we are flexible, the more we generate, the more we can increase.
‘All that I can assure fans is that their ambitions are matched by our’s, all within the parameters of never ever putting the club in jeopardy again.’
The health of Football League clubs has again been a subject of focus, with the news 52 of the 72 clubs outside the Premier League made losses totalling £388m in 2017-18.
With Pompey’s well-documented financial problems still in recent memory, it underlines why owners Tornante are keen to run their club on a sustainable basis.
Catlin believes those facts are understood by most fans and is why criticism is restricted to a vocal minority, as the club continues to progress.
He added: ‘I think it’s crazy to listen to a few people on social media.
‘That’s no way to run a business. Any business.
‘We just missed out on promotion in our second year in League One with 88 points, which will often get you promoted.
‘We’ve won a cup at Wembley this year and our players are in demand. We’re in a very good position.
‘So I think we’re doing something right.
'We are building this club sensibly and sustainably - we will not be blown of course in that regard.'