Regulators have visited the St Louis, Missouri, offices of investment bank and wealth manager Wachovia Securities seeking documents and records related to the company’s sale of auction rate securities.

They executed subpoenas seeking information concerning the firm’s sales practices, internal evaluations of the ARS market and marketing strategies, Missouri secretary of state Robin Carnahan said in a statement: “Hundreds of Missouri investors have called my office because of inability to access their money.”

In May 2008 Wachovia Corp, the parent company of Wachovia Securities and other affiliates, confirmed that it had received inquiries from the Securities and Exchange Commission and state regulators regarding ARS, according to an SEC filing.

On Tuesday this week, Swiss giant UBS announced plans to buy back as much as $3.5 billion of its auction rate securities from its customers after regulators in Massachusetts accused the firm of fraudulent practices related to the ARS market.