Mr Osborne has admitted making mistakes but denied wrongdoing
Shadow chancellor George Osborne will not be investigated by the Parliamentary Standards Commissioner.
Mr Osborne has admitted that he "made a mistake" by meeting Russian billionaire Oleg Deripaska several times.
But he vehemently denies claims he tried to solicit a £50,000 donation for the Conservative Party while on holiday in Corfu in the summer.
The commissioner's spokeswoman said: "The commissioner has received a complaint that has not been accepted."
She refused to say who had made the complaint to John Lyon, who has held the post since January.
The Electoral Commission has already said it will not investigate Mr Osborne.
It is illegal for someone not on the UK electoral roll to make donations to a UK political party.
Financier Nathaniel Rothschild has claimed Mr Osborne tried to solicit £50,000 for the Tories from Mr Deripaska while on holiday in Corfu in August.
Mr Osborne has always denied this.
During prime minister's questions last week, Gordon Brown said: "This is a very serious matter indeed and I hope it is investigated by the authorities."
However, the Electoral Commission said it would not launch an inquiry, as "soliciting a donation is not an offence".