Index funds at 50: how long can the party last before the passive investment candles blow out?

Too much of a good thing

Make just one investment and you own the whole market – any investor's dream right?

There is no doubting the influence of the passive investment phenomenon on modern equity markets. It is, after all, by far the easiest way to be diversified across the entire market. The proof of the pudding is in the eating as they say, and with over $16trn in global index funds since John McQuown and his team at Wells Fargo set up the first ever ETF five decades ago, it is fair to say numerous investors have had their slice of an increasingly large cake.   But as with any investment, and birthday cakes, one can have too much of a good thing and there is always a risk that things wil...