This paper is primarily concerned with investment by life offices and pension funds in British Government stocks with lives of more than 5 years, although there are important implications for all classes of investors. Investing in British Government stocks over the post-war period has become a highly technical process. The advent of the electronic computer has opened up an entirely new field of statistical data thus making some of the old methods obsolete. The paper illustrates some of the new techniques developed by the author and his colleagues. Other actuaries have also been developing new approaches and it is hoped that they will contribute to a lively and constructive discussion.

This paper has its origins in the authors' thoughts on the paper presented to the Institute by G. Heywood and M. Lander in 1961 under the title Pension Fund Valuations in Modern Conditions (J.I.A. 87, 314). Little claim for originality is made for the present paper: rather is it an attempt to consider in greater detail some of the problems raised by Heywood and Lander. We would also refer to the paper by C. E. Puckridge (J.I.A. 74,1) which, although we would not agree with some of its details, set out for the first time, in our opinion, some of the basic principles.