SPL clubs continued their financial recovery in season 2005/06 but made a collective loss of £9m for the year.
PricewaterhouseCoopers' annual review showed six clubs reporting a profit: Falkirk, Hibernian, Inverness, Kilmarnock, Motherwell and Rangers.
Net debt fell by £23m to £94m, with the main reductions at Celtic and Rangers but Hearts bucked the trend, with their debt rising by nearly £7m to £28m.
The collective wage bill remained stable at £93m during the season.
Hearts again stand out from the crowd, with their wage bill more than doubling to £10m - which represents 97% of turnover.
The six clubs reporting a profit all recorded a wage/turnover ratio of 50% or less, while the Old Firm account for almost £60m of the total wage bill.
The Tynecastle club increased revenue by £1.9m to £10.3m in 2006, thanks to their second place finish and Scottish Cup victory.
And the club are in debt to the Lithuanian bank group which owner Vladimir Romanov has a major shareholding in.
"The Hearts model is unsustainable but I would be more concerned if the debt was owed to a third party," said David Glen, a partner of PricewaterhouseCoopers.
The Edinburgh club have also just netted £7m from the sale of goalkeeper Craig Gordon, with the fee potentially rising by another £2m.
The importance of European football for the Old Firm was underlined, with Rangers' figures benefiting from a successful run in the Champions League and the injection of funds from their licensing agreement with JJB.
However, financial results recently released by the Ibrox club to 30 June this year showed their debt almost treble from the previous season, following their failure to qualify for the Champions League.
"The financial situation in Scottish football remains fragile and we are not going to see a return to the free-spending days that marked the early part of the decade," Glen added.
"Take Rangers as a case in point. In the 2005/06 season, their turnover drove beyond the £60m mark, the business generated an operating profit of £4.4m and the net debt was reduced to under £6m - thanks to a successful run in the Champions League and the JJB licensing agreement.
"Move forward just 12 months to season 2006/07, the financial results for which have just been published, and an operating lose of £5.1m arose whilst net debt increased to £16.5m.
"What a difference a season makes, and principally as a consequence of no Champions League participation.
"Similar issues will arise at other clubs, albeit on a different scale, but the above situation demonstrates the direct impact that success - or lack of it - on the park can have on a club's financial situation."