Illinois Statutes Chapter 710. Alternative Dispute Resolution § 30/25-5. Rules applicable to substance of dispute

(a) The arbitral tribunal shall decide the dispute in accordance with any rules of law that are chosen by the parties as applicable to the substance of the dispute. Any designation of the law or legal system of a given country or jurisdiction shall be construed, unless otherwise expressed, as directly referring to the substantive law of that country or jurisdiction and not to its conflict of laws rules.

(b) If the parties do not make the designation described in subsection (a) of this Section, the arbitral tribunal shall apply the law as determined by the conflict of laws rules that it considers applicable.

(c) The arbitral tribunal shall decide according to what is just and good (“ex aequo et bono”) or according to equity and good conscience (as “amiable compositeur”) rather than by the strict rule of law only if the parties have expressly authorized it to do so.

(d) In all cases, the arbitral tribunal shall decide in accordance with the terms of the contract and shall take into account the usages of the trade applicable to the transaction.