Passive funds have done investors a great service by cutting costs and helping ordinary savers access markets through ISAs and pensions. It may be an exchange-traded fund buying because the index tells it to, or an algorithm buying because the price is rising. The top five stocks in the UK market account for nearly 35% of its value. Voting and engagement matter, but passive funds are built on low costs and huge scale. And before you hand your pension to a rulebook, it is worth reading the rules.