Geoffrey Hancock along with his colleague John Manistre is one of the principal figures in actuarial analysis of segregated fund guarantees in Canada and the United States. Some of his papers can be found at the following URL's. .
http://www.actuaries.ca/meetings/general/1999/Hancock.pdf
http://www.actuaries.org/members/en/events/congresses/Cancun/ica2002_author/g/geoffrey_hancock.htm