Tower Group International’s situation has taken another turn for the worse, with news that the U.S. Securities and Exchange Commission is now investigating the struggling Bermuda insurer and reinsurer.

The company disclosed in a recent regulatory filing that it received a letter from the SEC stating that the regulatory agency “is conducting an investigation.” Tower Group also noted the SEC letter had an attached subpoena “for various documents.”

Tower said it would fully cooperate with the SEC investigation. It also noted, however, that the SEC letter stated: “the investigation and the subpoena do not mean that we have concluded that you or anyone else has broken the law,” or that the agency has “a negative opinion of any person, entity or security.”

Tower offered no further details of the SEC letter. But it was the second blow the company faced before Labor Day weekend that could threaten its future.

On Aug. 28, A.M. Best again issued more ratings downgrades for Tower Group, spurred by its growing net losses and uncertainty over whether it can carry its debts through an intended merger with ACP Re. The proposed merger was first announced in January and amended during the year. It’s expected to close this month but could face delays, A.M. Best noted.