The Owls, subject to a failed attempted buy-out in the summer, were rescued from possible administration by the Serbian-born businessman in November, 2010.
Since then, however, Mandaric has made no secret of his willingness to talk to potential investors in an attempt to restore the club to former glories.
Last summer, a deal appeared to have been struck with Azerbaijan oil and energy magnate Hafiz Mammadov.
Contracts were exchanged over the proposed sale of Wednesday only for the deal to subsequently flounder and then collapse in September.
After pulling the plug, Mandaric reiterated his desire for other parties to become involved at Hillsborough if they had the backing to take the Championship outfit forward and back into the top-flight.
Wednesday, one of the biggest clubs outside the Premier League but losing around £6m a year, have been on the radar of several would-be investors.
However, it is believed the Thai consortium has emerged as the most serious bidder and talks have been taking place in recent weeks.
Wednesday officials were last night standing by their insistence of only commenting publicly when there is concrete news to tell supporters.
But The Yorkshire Post understands that the talks with the Thai group remain on-going and are well advanced.
If these do come to fruition, Wednesday will become the latest Yorkshire club with foreign owners.
Leeds United were taken over by Italian businessman Massimo Cellino in April last year, while Prince Abdullah bin Mosaad bin Abdulaziz Al Saud bought a 50 per cent share of Sheffield United in September, 2013.
Egyptian-born businessman Assem Allam rescued Hull City from bankruptcy in December, 2010, although he moved to the East Riding in the Sixties and for the last 40-odd years has lived within a couple of miles of the club’s home stadium.
Wednesday are enjoying their best season in some time, with Stuart Gray’s men sitting 10th in the table and being just six points adrift of the play-offs.
The south Yorkshire club also came within a whisker of taking Premier League champions Manchester City to a replay in the FA Cup third round, only for James Milner to net a dramatic winner in stoppage time.