The Speaker of the House has decided not to refer a complaint, relating to the Prime Minister's management of his personal finances, to Parliament's Privileges Committee.
The Labour Party has claimed that, although Mr Key has a blind trust called Aldgate to administer his assets, some of them went into a separate company - Whitechapel - that is not blind to Mr Key.
Mr Key has denied any knowledge of Whitechapel's existence.
Labour complained that Mr Key misled Parliament about his knowledge of his investments.
The Speaker, Lockwood Smith, has considered the complaint and determined that no question of privilege is involved.
Mr Key says that as far as he's concerned, that's the end of the matter; but the Labour Party says it intends to keep asking questions about the arrangements made for his personal assets.