"As the foregoing history confirms, our references to "operational function" in Container Corp. and Allied-Signal were not intended to modify the unitary business principle by adding a new ground for apportionment. The concept of operational function simply recognizes that an asset can be a part of a taxpayer's unitary business even if what we may term a "unitary relationship" does not exist between the "payor and payee." See Allied-Signal, supra, at 791-792 (O'Connor, J., dissenting); Hellerstein, State Taxation of Corporate Income from Intangibles: Allied-Signal and Beyond, 48 Tax L. Rev. 739, 790 (1993) (hereinafter Hellerstein). In the example given in Allied-Signal, the taxpayer was not unitary with its banker, but the taxpayer's deposits (which represented working capital and thus operational assets) were clearly unitary with the taxpayer's business. In Corn Products, the taxpayer was not unitary with the counterparty to its hedge, but the taxpayer's futures contracts (which served to hedge against the risk of an increase in the price of a key cost input) were likewise clearly unitary with the taxpayer's business. In each case, the "payor" was not a unitary part of the taxpayer's business, but the relevant asset was. The conclusion that the asset served an operational function was merely instrumental to the constitutionally relevant conclusion that the asset was a unitary part of the business being conducted in the taxing State rather than a discrete asset to which the State had no claim. Our decisions in Container Corp. and Allied-Signal did not announce a new ground for the constitutional apportionment of extrastate values in the absence of a unitary business. Because the Appellate Court of Illinois interpreted those decisions to the contrary, it erred."
So on that basis they vacated the appellate court's decision. They did point out that although the trial court had concluded that Mead and Lexis-Nexis were not unitary, that issue wasn't considered in the appeal. The appellate court was invited to consider that question on remand.
Since the trial court already determined that they weren't unitary, it seems logical that IL will lose this case. We will be interested to see how it turns out.