Bargaining Chip (1960, 1964) (7)

[James A. Landau]

Just a guess:

During a lengthy negotiation, both sides make offers that were not part of
the original discussion.  Some of these offers are the "bargaining chips" we
have been discussing.  The process of offering these offers is sometimes known by
the metaphor, probably derived from poker, of "sweetening the pot".

Metaphorically such offers, whether or not they make the final agreement, are
"pieces of the final agreement", and "chips" = "pieces", doesn't it?  Hence
"bargaining chips".

    - James A. Landau