In its Keogh decision the Supreme Court held that although the Interstate Commerce Act did not exempt railroads from antitrust liability, a private plaintiff may not recover treble damages based on an allegedly monopolistic tariff rate filed with a federal agency. Keogh very likely grew out of Justice Brandeis's own zeal for regulation and his concern for the protection of small business — in this case, mainly shippers whom he felt were protected from discrimination by filed rates. The Supreme Court's Square D decision later conceded that Keogh may have been “unwise as a matter of policy,” but reaffirmed it on the ground that Congress had had ample opportunity to overturn it but had not done so.
Under the doctrine consumer overcharge actions challenging a “filed” rate will be dismissed. The rate need not have been actively reviewed for accuracy or public interest considerations — indeed, it need not have been reviewed at all in any meaningful sense. The doctrine operates as a rule against collateral attack: once filed, a rate may not be collaterally attacked in the courts. However, an objector may be able to ask the regulatory agency to review a rate within its jurisdiction. Of course, that proceeding would not be in antitrust and would not provide treble damages and attorney's fees as an inducement.
The doctrine becomes more complex and even less rational under partial deregulation. Today, for example, some rates must be “filed” with the overseeing agency although the agency has little power to adjust the rates except in extraordinary circumstances.
Supreme Court analysis of filed rates has focused on rates filed with federal agencies. Several lower court decisions have extended the doctrine to rates filed with state regulators, generally without distinguishing the issues. Extending the doctrine to state agencies raises the troublesome issue that rate filings may serve to confer an effective antitrust immunity in situations where antitrust’s “state action” doctrine would not apply. The filed rate doctrine does not contain anything equivalent to the “authorization” or “active supervision” requirements that the state action doctrine compels. For example, a state provision may authorize an exclusionary tariff, giving no thought to competitive consequences. The state agency in turn may approve such requests with little or no evaluation. While the provision in question would not survive scrutiny under the state action doctrine, the tariff filing itself may have effective immunity under the filed rate doctrine. The Third Circuit’s McCray decision applied the filed rate doctrine to price fixing among title insurers, expressly rejecting the argument that application required the defendant’s to show “meaningful review” by the state regulator.
The filed rate doctrine should not be applied as an additional bar to antitrust enforcement. Rather, application of the antitrust laws should rest, as it usually does, on the power of the agency to immunize conduct and the extent and nature of its supervision.
Hovenkamp, Herbert J., "Antitrust and the 'Filed Rate' Doctrine: Deregulation and State Action" (2012). Faculty Scholarship. 1851.