(business) A poison pill giving current shareholders of the targetedcompany the right to purchase additional stock at a discount before a potential takeover, so that the potential acquirer risks discriminatory dilution in the target company. The threshold level therefore effectively sets a ceiling on the amount of stock that any shareholder can accumulate before launching a proxy contest.
1994, Milton L. Rock, Robert H. Rock, Martin J. Sikora, The Mergers and Acquisitions Handbook
There has been no definitive or pervasive ruling as yet on flip-ins, but courts in specific cases have limited their applications.