Investigators say they have found no evidence of fraud at a hospital which admitted more than 100 patients had been harmed by treatment delays.
A whistleblower had alleged patients were removed from lists at Kettering General Hospital because national targets were being missed.
The hospital denied "fiddling" but admitted inappropriate "filtering" to remove patients from waiting lists.
NHS Protect said it had carried out inquiries and no fraud was found.
The organisation, which investigates potential fraud in the NHS, said having conducted preliminary inquiries it would not be carrying out a full investigation.
'A lot of concern'
In May, the BBC reported allegations by David Phelan, who was also a trust governor at the time, that waiting lists had been "fiddled" to remove patients.
A hospital review found that 138 patients were harmed - including one who had substantial sight loss - as a result of the long waits.
The hospital admitted using inappropriate filtering of its data to remove patients, but said: "Allegations brought by the former member of staff that this was done to deliberately make our figures look better and to avoid fines from our commissioners for long waiting patients is entirely false."
It quoted the findings of a report which said the filters were "well-intentioned, if misguided, tactical efforts to extract performance data which created a false sense of comfort and control".
Fiona Wise, interim chief executive at the hospital, said the trust had been given the "all clear".
"There has been a lot of concern about fiddling the waiting list," she said. "NHS Protect have been looking at the issues and they have confirmed to us that absolutely there was no fraud."
NHS Protect said: "After undertaking enquiries about Kettering General Hospitals NHS Foundation Trust, it is our view that there is no evidence of fraud against the NHS in the claims made, and it is also unlikely fraudulent activity will occur in the future in relation to this issue at the trust."