Los Angeles-based Goldberg Law PC said March 18 it filed a potential class action lawsuit against Williams Partners LP. The action seeks to represent investors who purchased or otherwise acquired Williams Partners units between May 13 and June 19, 2015.

The action has a motion deadline of May 6. The class in this case has not yet been certified, the law firm noted.

The law firm noted that on May 13, 2015, Williams Partners made public an agreement according to which its parent, The Williams Cos. Inc., would purchase all publicly held Williams Partners common units.

However, the investing public did not know that Williams Cos.' management was also at the time in discussions with Energy Transfer Equity LP regarding a proposal from Energy Transfer to acquire all of Williams.

That agreement, announced later, required Williams to terminate its proposed merger with Williams Partners.