Sunderland owner Ellis Short has agreed a deal to sell the club following their relegation from the Championship.
The Black Cats have faced questions over the running of the club following their descent down the football ladder, with their plight this term seeing them become the first team in 33 years to finish bottom of the top two tiers in successive seasons.
Donald, who has also supported Oxford United as an investor and shirt sponsor over the past decade, will now relinquish control of Eastleigh should the takeover be approved by the EFL.
"It is no secret that I have been trying to sell Sunderland, but I have waited until the right group came along that have the experience, finances and plan to take this great club back to where it deserves to be," read a statement from Short.
"Overall, my chairmanship has not gone the way I would have wished; the many high points of a decade in the Premier League have been overshadowed by the low points of the last two terrible seasons. I was therefore determined to ensure that I leave Sunderland in the best possible hands and in the best possible state to turn the corner.
"To achieve this, higher offers from less qualified buyers were rejected, and I have paid off all debts owed by the club to leave it financially strong and debt free for the first time since years before I owned it. Assuming Stewart and his group win EFL approval, it only remains for me to wish them, and all associated with the club, the very best for the future.
"I will be a Sunderland fan for life, and hope to return as a fan to watch them climb back to where they belong."