A stockholder has sued Blue Nile Inc. and accused the company's board of breaching their fiduciary duties in relation to the company's proposed acquisition by an investor group.

In a putative class-action suit filed in the Delaware Court of Chancery, the stockholder claimed the board failed to disclose all material information that was required to allow the stockholders to cast a fully informed vote on the proposed merger.

Among other things, the suit is seeking an order preliminarily and permanently enjoining the proposed merger, a finding that the board is liable for breaching their fiduciary duties, and an award of attorneys' and other fees and expenses.

While dismissing all allegations, the board provided supplemental disclosures in a Form 8-K filed Jan. 24.

In November 2016, the investor group composed of funds managed by Bain Capital Private Equity LP and Bow Street LLC agreed to acquire 100% of the outstanding shares of Blue Nile in an all-cash transaction worth about $500 million.