MAPF holds preferred shares. What is different than preferred share indices (or the ETFs that follow these) is that holdings are actively traded, not passively held.
This is described best on the funds site http://www.himivest.com/ which says:
The success of the fund’s trading is showing up in the very good performance against the index
the long term increases in sustainable income per unit. As has been noted, the fund has maintained a credit quality equal to or better than the index; outperformance is due to exploitation of trading anomalies.
Again, there are no predictions for the future! The fund will continue to trade between issues in an attempt to exploit market gaps in liquidity, in an effort to outperform the index and keep the sustainable income per unit – however calculated! – growing.
A comparison of MAPF performance with the benchmarks and indices the the end of February 2013 is shown in the table below (click to enlarge).
The portfolio average 'yield to worst' is 3.87% at the end of March 2013. With favourable tax treatment of dividends from the preferred shares, that is equivalent to over 5% of interest (other income) from a GIC or a MIC. The trading makes up the difference in the returns and adds 3-4% to the return relative to the benchmark TXPR or a popular ETF (Blackrock's CPD) over the last year. These returns are after expenses but before fees. With fees in the 1% range for small holding, paying for the extra performance is certainly worth it.