ANSWER
Just as you would want to know how familiar the sponsor is with the passive investors in their deals, you would also be interested in knowing how long they’ve known one another. Promising signs are sponsors who have handled capital of the same passive investors on multiple deals. The presumed reason being those investors are happy with the returns and want to come back for more. As well, the long-term partnership signals that they are pleased with the level of communication, attention to detail, management style, and patterns of behavior of what seems to be a credible and sponsor.