(Bloomberg) -- Leveraged ETFs that offer the tantalizing prospect of doubling or tripling the daily returns of an individual stock are famously risky for investors who buy them. "Therefore, now banks are trying to develop the crash-put market in order to hedge all these leveraged ETFs." Behind the GrowthTo understand the growth in demand for crash puts this year requires a look at the financial plumbing that allows these leveraged ETFs to exist. The higher premiums are in part a result of the surge in popularity of leveraged ETFs tracking both indexes and individual stocks. Yet as the crash put market grows along with leveraged ETFs, the complexity and opacity of these niche products has raised concerns among critics.