Because KiwiSaver is primarily a retirement investment scheme, most investors should have a medium to long term investment horizon.

With the exception of those saving for a first home, most KiwiSaver members will be investing in a retirement investment fund until the date of eligibility for National Superannuation (which is currently 65 years of age). Under KiwiSaver rules, even investors close to retirement will have a time horizon of at least 5 years.

It is Brook's view that because KiwiSaver members' investment time horizons will generally incorporate at least one full business cycle (which can take up to 10 years), their portfolios should contain significant weightings to Growth Assets. Those members approaching retirement age (say 5 to 7 years before retirement) may wish to select a portfolio which includes Income Assets for their retirement.