Interest in too big to fail (TBTF) resolutions of insolvent large complex financial firms has intensified in recent years. TBTF resolutions protect some in-the-money counterparties of a targeted insolvent firm from losses that they would suffer if the usual bankruptcy resolution regimes used in resolving other firms in the industry were applied. Although special TBTF resolution regimes may reduce the collateral spill-over costs of the failure, the combined direct and indirect costs from such “bailouts” may be large and often financed in part or in total by taxpayers. Thus, TBTF has become a major public policy issue that has not been resolved in part because of disagreements about definitions and thereby the estimates of the benefits and costs. This paper explores these differences and develops a framework for standardizing the definitions and evaluating the desirability of TBTF resolutions more accurately.