Yugoslav Bonds Boosted by Peace Plan: Defaulted Yugoslav bonds soared after Bosnian, Serbian and Croatian leaders agreed to the plan and the U.N. Security Council suspended economic sanctions against Serbia. Yugoslav New Financing Agreement bonds--issued as part of a debt rescheduling in the 1980s before the country splintered and descended into civil war--rose 1.5 points to 46.5 bid and 48.5 offered in London. The bonds have risen 38.6% in value since early September. They are up 12.6% since Monday, before the peace plan was announced. Sanctions prohibited investors from buying or selling bonds that originated in debt sold by Serbian companies and banks.