The Owls, who host promotion rivals Huddersfield Town at Hillsborough today, have pushed the boat out on wages and sit second in the League One table.
But Mandaric has wiped out debts that once crippled the club and will also back manager Gary Megson in the New Year transfer window.
Speaking on the first anniversary of his takeover, the former Leicester City and Portsmouth owner, 73, revealed that he wants the Owls to be self-sufficient next season.
He also stressed that he had ‘no regrets’ about taking up the challenge and was in no rush to leave.
“I would only have regrets if I had not come to this football club,” he said. “I can’t say how long I will be here but I am very enthusiastic, I love this club and I ask people to trust me.”
Mandaric paid around £9m to secure ownership of Wednesday, whose debts had reached over £25m as a consequence of over-spending in the wake of relegation from the Premier League.
The money subsequently invested in players has been the envy of most clubs in League One although manager Gary Megson insisted this week that Huddersfield and Charlton Athletic had spent more.
“Whatever I do here, I want to do it right, properly, for the supporters,” said Mandaric, “I am not doing anything more or anything less than I would expect from myself as a chairman who gave a commitment to the club.
“Right now, I am financing this club myself in League One but my objective is for the club not to be depending on any one individual.
“Once we get to the Championship, I think we should be able to break even,” he said. “There will be an extra £5m from the TV and the Premier League plus, I am quite sure, there will be more enthusiasm from supporters, sponsors, and we can start to look at international contributions as well.
“It is possible to break even in the Championship but our losses are about £4m to £5m in League One,” he said. “You want a club that exists and goes forward without other people adding to it but right now that is not possible and I knew that when I took over.”
Mandaric says the priority next month is the retention of loan players including Wolves defender Danny Batth, Derby County goalkeeper Stephen Bywater and Stoke City winger Ben Marshall.
Bywater makes his final appearance on loan this afternoon.
“It’s a tough league and you want to be competitive,” said Mandaric. “The priority is to secure the loan players who are helping drive the team – but if Gary can see an opportunity to enhance the team in any other way I will give him support.”
Over 26,000 supporters are set to attend today’s game with fourth-placed Town only four points behind the Owls, who are five points adrift of leaders Charlton.
The game will be extra special for midfielder Tommy Miller, who returns to Hillsborough as a Town player for the first time since leaving the Owls in the summer.
The former Ipswich Town and Sunderland player, 32, spent two seasons in South Yorkshire and says both clubs are good enough to win promotion.
“This could be a Championship fixture next season. Hopefully, it will be, especially from our point of view,” he said. “It is a massive game and you won’t get many bigger in League One this season, or even the Championship. We are looking forward to it. To have two big Yorkshire clubs doing so well this season is very good for the region.”
Miller says today’s game was the first he looked out for when the fixtures were released.
“I think managers want to bring their own players in and that is what Gary Megson has done,” he said. “They are doing very well, you can’t dispute that, and now that is the case, he will be judged on this season. At the moment, they are up at the top of the league and they are doing well. It will be nice for me to go back and see a few faces.”
Town striker Jordan Rhodes, meanwhile, is the son of Owls goalkeeping coach Andy.