In recent years, investors have poured tons of money into exchange-traded funds, fueling a boom in the industry.

To meet the evolving demand, fund companies started offering all kinds of wild ETFs, sometimes employing extraordinary amounts of leverage.

However, it's possible that the industry might've gotten ahead of itself.

Even though assets in ETFs continue to rise the number of funds is falling.

From Lazslo Birinyi:

Despite the overall rise in assets (to a record $1.3T), the total number of available funds fell to 1,441.  Six new funds were released in September, while twenty-four  were liquidated.   Last month was the highest on record in terms of fund liquidations.  The majority of liquidations came from UBS which closed twelve of their VIX focused ETNs and Direxion which closed eight of their leveraged funds.

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