12-month acquisition period
(1) 12-month acquisition period The term “12-month acquisition period” means the 12-month period beginning with the date of the first acquisition by purchase of stock included in a qualified stock purchase (or, if any of such stock was acquired in an acquisition which is a purchase by reason of subparagraph (C) of paragraph (3), the date on which the acquiring corporation is first considered under section 318(a) (other than paragraph (4) thereof) as owning stock owned by the corporation from which such acquisition was made).