Unocal will seek another takeover defense.

The Los Angeles parent of Union Oil said in a proxy statement for its April 28 annual meeting that it will ask shareholders to approve a plan to issue 100 million new preferred shares. Unocal acknowledged that the new shares could help repel future takeover attempts but said it has no current plans to use the stock for that purpose. Unocal’s earlier takeover defenses were put to the test last year when Texas oilman T. Boone Pickens Jr. sought control of Unocal. Pickens was repelled, but the takeover defenses proved largely ineffective.