It's also possible that Vanguard just delivers the same products as their competitors, just at a significantly lower price (management cost). Keep in mind also

It's also possible that Vanguard just delivers the same products as their competitors, just at a significantly lower price (management cost). Keep in mind also that "growing" in this context doesn't refer to huge profits (as far as I know). As far as I can see, as a non-expert, Vanguard just offers the same products as everyone else, except at half the yearly management cost. I mean, when you're looking for some index fund, and Vanguard is one third the cost, is it any surprise they're taking away customers from the incumbents? EDIT: For example, here's TLT (0.15% p.a.) vs Vanguard's long term bond etf (0.07% p.a.): https://personal.vanguard.com/us/funds/snapshot?FundId=3144&FundIntExt=INT https://personal.vanguard.com/us/funds/snapshot?FundId=3144&... https://www.ishares.com/us/products/239454/ishares-20-year-treasury-bond-etf https://www.ishares.com/us/products/239454/ishares-20-year-t...