claim the benefit of the contract and simultaneously avoid its burdens would both disregard equity and contravene the purpose underlying the enactment of the [FAA]. Id. at 418 (internal quotations and citations omitted) (emphasis added). In the specific situation where, as in this case, a signatory seeks to enforce an arbitration agreement against a non-signatory, the doctrine es-tops the non-signatory from claiming that he is not bound to the arbitration agreement when he receives a “direct benefit” from a contract containing an arbitration clause. Id. (internal quotations and citations omitted); see also Am. Bankers Ins. Group, v. Long, 453 F.3d 623, 628 (4th Cir.2006); R.J. Griffin, 384 F.3d at 162; Am. Bureau of Shipping v. Tencara Shipyard S.P.A., 170 F.3d 349, 353 (2d Cir.1999) (<HOLDING>). For example, in Schwabedissen, International
holding that an exception to the rule that a nonsignatory cannot invoke arbitration exists when under agency or related principals the relationship between the nonsignatory and a signatory is sufficiently close that the only way to avoid eviscerating the arbitration agreement is to allow the nonsignatory to compel arbitration holding that state law governs whether an arbitration clause is enforceable against a nonsignatory under the faa holding that nonsignatory was estopped from denying applicability of arbitration clause where nonsignatory received direct benefits from contract including lowered insurance rates and the ability to sail under the french flag holding nonsignatory defendants who were sued separately from signatory defendants on same claims could enforce arbitration agreement under this equitable exception further nonsignatory defendants were undisputedly agents or servants of signatory defendants holding that nonsignatory to ib guarantee agreement possessed no authority from fcm  express implied or apparent  to conduct business relating to commodity pools nonsignatory to ib guarantee agreement was never an agent of any kind for fcm