Press Association Sport understands all parties concerned have signed a contract and Mandaric's takeover must now be rubber-stamped by the club's shareholders at an extraordinary general meeting.
The 72-year-old Serbian-born businessman, who will now resign as chairman at Leicester, has agreed a £7million settlement with the club's main creditor, the Co-operative Bank, who were owed £23million.
Other loan note holders, including former Owls chairman Dave Allen, who was owed £2.4million and turned down an initial offer of £250,000 last week, have reached agreement after talks between the respective parties' lawyers yesterday extended through the night.
A club source told Press Association Sport: "A deal for Mandaric to buy the club has been agreed by everybody. It will all have to be voted on by shareholders, but the reality is that all the senior people that need to sign up to the deal have signed - the bank and all the loan note holders, everybody has agreed.
"Milan has had to put his hand in his pockets. He's had tremendous feedback from Wednesday fans since becoming involved and that made him more determined to do the deal."
Source: PA
Source: PA