Green’s Dictionary of Slang

bang n.2

[weak use of SE]

1. a lie.

[UK]Partridge DSUE (8th edn) 47/1: C.20.

2. (US Und.) information.

[US] ‘Und. “Lingo” Brought Up-to-Date’ in L.A. Times 8 Nov. K3: BANG: A tip off; information.