Two influential proxy advisory firms on Wednesday recommended that Family Dollar’s shareholders accept an $8.5 billion takeover offer from competing discount chain Dollar Tree, dealing a blow to a rival bid from Dollar General.

While Dollar General’s $9.1 billion bid is valued at $80 a share — versus $74.50 for Dollar Tree’s bid — it carries significant regulatory risks, Institutional Shareholder Services and Glass Lewis said in a note to clients.

Specifically, ISS cited a disclosure earlier in the week by Family Dollar that Dollar General would likely be forced by regulators to divest between 3,500 and 4,000 stores to get its deal done.

Dollar General, which previously estimated that the Federal Trade Commission would require it to divest no more than 1,500 stores, didn’t comment Wednesday.

Dollar General’s silence on the issue this week “speaks volumes,” ISS said in its report.

Family Dollar shareholders are slated to vote on Dollar Tree’s offer Jan. 22, a month after the vote was delayed to give Dollar General more time to make its case.

Earlier this week, Dollar Tree CEO Bob Sasser told investors he will withdraw his bid if the vote gets delayed again, and noted that recent weakness in Family Dollar’s business makes a merger more urgent.

Dollar Tree said it estimates it will have to close fewer than 300 stores to get its deal approved by the FTC.