["Real Estate Economics, EarlyView. ", "\nAbstract\nThis article examines how collaboration between listing and selling agents influences housing market outcomes and how these effects differ across the institutional environments of conventional and foreclosure (real estate owned [REO]) transactions. We develop a conceptual framework linking seller objectives, institutional constraints, and agent incentives to heterogeneous collaboration effects across market segments and test its predictions using more than 150,000 single‐family sales from the Dallas–Fort Worth metro area. We estimate jointly determined price and time‐on‐market (TOM) equations with detailed agent controls and distinguish between repeated interactions within specific agent pairs (depth) and broader patterns of collaborative activity (breadth). In conventional sales, neither dyad depth nor collaboration breadth materially affects prices or TOM once agent characteristics are accounted for. In the REO segment, repeated interactions beyond the first two joint sales are associated with price discounts of roughly 2%–3%, whereas collaboration has little effect on TOM. Further analysis reveals that the REO discount originates in the negotiation stage, as listing agents become progressively more willing to accept prices below the original list price as collaborative relationships deepen.\n"]