Arbitration under Thai law rests on consent. Section 11 of the Arbitration Act B.E. 2545 (2002) requires an arbitration agreement to be in writing and signed by the parties. This may also be satisfied by communications, an unchallenged allegation in pleadings, or incorporation by reference to a document containing an arbitration clause. A non-signatory cannot, as a general rule, be compelled to arbitrate merely because it participated in the transaction, received a benefit, or belongs to the corporate group of a signatory. Thai law nevertheless permits arbitration agreements and awards to affect third parties indirectly in limited circumstances. Under section 24, an arbitration clause is separable from the main contract; the invalidity of the contract does not invalidate the clause. In Supreme Court Judgment No. 3918/2563, an apparent sales contract concealed a construction contract and was void under the Civil and Commercial Code. However, the concealed construction contract and written arbitration clause remained effective. The tribunal had jurisdiction, and its award was enforceable under the Arbitration Act. Under the Arbitration Act, when a claim or liability is validly transferred, the transferee is bound by the related arbitration agreement. This includes assignment, transfer of obligations, legal succession, and subrogation. Depending on the facts and contract and agency law, consent may arise through execution by an authorized agent, ratification, assumption of obligations, or conduct accepting the contract and its arbitration clause. Thai law respects separate corporate personality. The group-of-companies doctrine has no statutory basis under the Arbitration Act, while alter egos or sham allegations require compelling evidence and an identifiable legal basis. Supreme Court Judgment No. 9161/2568 illustrates the procedural treatment of non-signatories. A consultancy contract required LCIA arbitration seated in Dubai. When the employer sued a consultant and his spouse in Thailand concerning a housing loan, the court disposed of