cork, n.³ — Green’s Dictionary of Slang

cork n.³

[he bobs up and down like a cork, for lack of pecuniary ‘ballast’]

a bankrupt.

1873		Sl. Dict. 129: Cork, a broken man, a bankrupt. Probably intended to refer to his lightness, as being without ‘ballast’.
1889–90		Barrère & Leland Dict. of Sl., Jargon and Cant.
1890–1904		Farmer & Henley Sl. and Its Analogues.