Correction: The headline should read ISS encourages Spirit shareholders not to accept Frontier’s offer but ISS urges Spirit stockholders to choose JetBlue over Frontier.

(Reuters] – Institutional Shareholder Services Inc (ISS), a proxy advisory firm, has urged shareholders to Spirit Airlines (NYSE:) To vote against Frontier Group Holdings’ proposed merger

JetBlue Airways (NASDAQ) Inc’s rival offer of $30 a Share is superior financially, ISS reported Tuesday. The cash consideration was significantly higher than Frontier’s mostly stock deal.

Frontier’s Cash-and-Stock Offer for Each Share of Discount Carrier was $22.31 as of Tuesday.

In a Tuesday report, the proxy advisory firm claimed that “The Spirit Board’s opinion that Frontier mergers offer a safer route to regulatory approval does not support any guarantee of shareholder value in the event regulatory rejection occurs.”

Ted Christie, Chief Executive of Spirit, a Florida-based company, stated last week that shareholders are unlikely to vote against Frontier’s proposed merger.

Additionally, the advisory firm stated that the board decided to skip an auction process. This raises concerns for shareholders. In light of potential regulatory risks and JetBlue offering a $200m termination fee, it is possible for the board to fail to negotiate a refund fee with Frontier.

JetBlue responded to the ISS report by saying that it “reports on the flawed process the conflicted Spirit Board used, which only emphasizes the need that Spirit’s Board now come to this table to negotiate.” JetBlue corrects the headline. It now says that ISS calls on Spirit shareholders reject Frontier, but not ISS to urge Spirit shareholders choose JetBlue’s offer over Frontier.