What do you do when, following strong rises in stock markets, decent yields from UK equities are getting harder to come by? Some investors might consider fixed-interest products, such as corporate bonds, where yields are higher, even if the potential for capital gains are much less.

But in the US there is another way and this alternative is slowly gaining traction in the UK. Growing numbers of investors can put their money into covered call funds which use derivatives on top of traditional equities to generate above-average income yields.