Word describing people who need to establish trust, But aren't friends

I'm looking for a single word that would describe two people that need to establish trust between them but aren't friends. An example might be buyer and seller, if person A buys a car from person B. Both of them need to have some trust however they won't meet each other ever again.

Thanks.


Solution 1:

"Counterparties" is the word that is used in the financial industry for parties at either end of a transaction. It's most frequently seen as part of the phrase "counterparty risk", which is the risk that a counterparty won't be able to hold up its end of the bargain.