Sept. 4 (Bloomberg) — F-Squared Investments Inc., one of the largest managers of investment products built using exchange-traded funds, said U.S. regulators were considering a civil action against the firm over performance claims made in the firm's advertising materials.

The firm, which oversees $27.7 billion, received a Wells notice from the Securities and Exchange Commission on Aug. 13 informing it that SEC staff recommends an action, the Wellesley, Massachusetts-based firm said in a filing submitted Aug. 29.

F-Squared, whose assets have grown from about $3 billion in 2011, had told clients in October it was under investigation by the SEC over its advertised performance records from April 2001 through September 2008, which the regulator later found contained errors and weren't based on actual client assets. F- Squared is among the most prominent firms in a fast-growing investing niche, specializing in actively managed accounts that use ETFs instead of single stocks or bonds as their holdings.