Abstract: This paper builds a dynamic model of corporate financing where financial slack arises because financiers possessing bargaining power extract financing rent. Despite the absence of fixed transaction costs, firms finance in lumps to bargain infrequently and typically before exhausting internal funds to strengthen their outside options. Continuation value increases rent, rationalizing large financial slack of `growth' firms. Firms able to quickly switch financiers finance frequently while maintaining funding reserves that exceed investment needs, whereas firms without such options finance only when funds are depleted and may forgo investment despite the ability to finance it. Investment irreversibility may amplify financing rent.