What are the limits for ETFs?

February saw the launch of Pimco Source’s active short maturity ETFs. Previous to that and further down the active end of the spectrum, Source launched its MAN GLG Europe Plus ETF. These strategies and others like them are pushing the envelope in terms of what is available within the ETP wrapper with increasing regularity.  From a legal perspective, there are no real boundaries as to what constitutes an ETF; any that do exist come from investor perception. Providers are guided by what we expect of an ETF and generally speaking the largest products are still those that track liquid, broa...