Thomas

An investment advisor and related defendants appeal the order denying their petition to compel an investor’s successor in interest to arbitrate claims alleging the defendants mismanaged the investor’s accounts. The trial court denied the petition on the grounds that the claims against two of the six defendants were not subject to arbitration because those defendants were not parties to any arbitration agreement, and that there was a possibility of *609 conflicting rulings on common questions of law or fact if arbitration of the claims against the other four defendants were ordered. We reverse.

I

FACTUAL AND PROCEDURAL BACKGROUND

A. The Arbitration Agreements

Before her death, Katherine W. Thomas, an elderly widow, opened three investment accounts with defendants Ameriprise Financial Services, Inc. (AFSI), 1 a subsidiary of Ameriprise Financial, Inc. (AFI). Defendant Stephen M. Westlake (erroneously sued as Steven M. Westlake), a registered representative of AFSI, acted as the securities broker and investment advisor for these accounts.

Katherine opened the first investment account in her capacity as trustee of the John W. and Katherine W Thomas Family Trust (the…