BY CASEY SMITH, Tulsa WorldTwo Williams Cos. investors filed a putative class action suit against the Tulsa-based energy company Monday, alleging that the $37.7 billion sale to Energy Transfer Equity announced last week undervalues Williams Cos. The lawsuit was reported by Law360, a subscription-based legal news service operated by LexisNexis subsidiary the Portfolio Media company. According to the Law360 report, the suit against Williams was filed in Delaware Chancery Court by Williams Cos.