Firms under scrutiny regarding certain bidding practices Antitrust and securities regulators are considering charges against a handful of large banks, bond insurers and some of their employees as part of an investigation into certain municipal-bond investments. Bank of America, UBS AG and bond insurer Financial Security Assurance Holdings Ltd. last month received notices from the Securities and Exchange Commission indicating civil enforcement action may be taken against them for potentially violating federal securities laws about bidding practices on contracts that manage municipal funds. The "Wells notices" sent by the SEC, which the companies disclosed in regulatory filings, also give the...