JUSTICE O'CONNOR, concurring in part.
I agree with the Court that the case is not moot, and that portions of the Illinois Business Take-Over Act, Ill.Rev.Stat., ch. 121 1/2, 137.51 et seq. (1979), are invalid under the Commerce Clause. Because it is not necessary to reach the preemption issue, I join only Parts I, II, and V of the Court's opinion, and would affirm the judgment of the Court of Appeals on that basis.