The parent company of Wrightbus made a £1.35m donation to a religious charity when the County Antrim bus builder was in deep financial trouble, the BBC's Spotlight can reveal.
Wrightbus went into administration in September 2019 owing creditors £58m.
In January 2019 its parent firm Cornerstone made the donation to Green Pastures Church.
Jeff Wright was the controlling shareholder of Cornerstone and a director of the church.
A corporate governance expert told Spotlight that for the donation to be made at that time "raises a conflict of interest which would be very, very severe".
Clive Grace, a former director-general of the Welsh Audit Commission, said the money paid out in the donation could have been made available to Wrightbus to help it restructure.
In a statement, Jeff Wright said the business failed because it experienced "a sudden and unexpected drop-off in orders".
The wider Wright family said they had acted appropriately and lawfully at all times.
Cornerstone made a series of large donations to Green Pastures, mostly at a time when the wider Wrights Group was doing well.
However, Wrights Group management accounts for 2018 show a pre-tax loss of £13.6m.
The Spotlight programme also looks at other transactions in the run-up to the administration that raise questions about how the business was being run.
Wrightbus was bought out of administration in October last year by the English industrialist Jo Bamford.
He has been on a recruitment drive since completing that deal and the factory now employs 400 people.
You can watch Spotlight on BBC One Northern Ireland at 22:35 on Tuesday or watch it on the BBC iPlayer after broadcast.