Edward Owens, the portfolio manager of Vanguard Health Care Fund, will retire on December 31. Owens, a senior vice president and partner of Wellington Capital Management, has managed the fund since it began in 1984. Jean Hynes, the associate portfolio manager, will assume the management role when Owens retires. She is a senior vice president and partner at Wellington Management, and has served on the Health Care Fund team for nearly 20 years.