AbbVie reconsidering $54.6 billion acquisition of Shire

US drugmaker AbbVie (NYSE: ABBV) has told Ireland-headquartered Shire (LSE: SHP) of its board of directors' intention to meet on October 20 to discuss the planned $54.6 billion acquisition of the latter, as  announced in July.

AbbVie's Board will consider, among other things, the impact of the US Department of Treasury's proposed unilateral changes to the tax regulations announced on September 22, including the impact to the fundamental financial benefits of the tax inversion transaction.

As a result, AbbVie has notified Shire under the cooperation agreement that AbbVie's board intends to meet to consider whether to withdraw or modify its recommendation. Under the agreement, AbbVie must provide three business days' notice of any intention to consider a change in recommendation. Accordingly, AbbVie's board plans to meet on October 20, unless Shire agrees to waive the notice.