EX-99.77Q1 OTHR EXHB 4 q771.txt ADVISORY CONTRACT VANGUARD(R) Fixed Income FUnds VANGUARD High-Yield Corporate Fund VANGUARD Long-Term Investment Grade Fund VANGUARD GNMA Fund Addendum to Wellington Management Company LLC Agreement DATED MAY 1, 2006 For Wellington Management Company LLC,an amended agreement changes the process for the quarterly calculation of asset-based fees. The calculations now will be based on the average daily net assets managed by the advisor, rather than the average month-end net assets.