Shamrock boosted its stake in Foote, Cone.

Shamrock Holdings said it has increased its investment to 7.4% from 5.2% and said it will seek clearance from federal antitrust agencies to purchase up to 25% of Foote, Cone & Belding Communications, a Chicago-based advertising agency. Shamrock also criticized Foote, Cone’s recent adoption of a “poison pill” anti-takeover plan. If the plan is not rescinded, Shamrock said, it might seek shareholder votes to force such an action. Burbank-based Shamrock is owned by the Roy E. Disney family.