The Delaware Court of Chancery has dismissed a $428 million shareholder derivative suit accusing The Williams Cos. Inc. board of using a planned $13 billion acquisition to torpedo the company's doomed merger with Energy Transfer Equity.

Williams investor Walter E. Ryan Jr. said the board of the Toledo-based energy firm had initially pursued the $13 billion purchase of its own master limited partnership, Williams Partners, as a defensive measure to fend off Williams' proposed $38 billion tie-up with ETE—only to later pull the plug on the deal and then watch the blockbuster merger with ETE fall apart.

In court filings, Ryan attacked the independence and disinterestedness of the board in approving the Williams Partners deal, saying a majority of directors were motivated by their dislike of ETE and a desire to entrench themselves.