Last December, Credit Suisse Group AG (CS), closed two very popular ways of betting on oil to the public.

Both were exchange-traded notes (ETNs) pegged to oil prices, and both had been multi-billion dollar plays that allowed regular people to profit from on swings in oil prices.

But while there’s no public price listed anymore, financial institutions keep trading these “zombie” notes…

And it’s massively distorting oil prices, as we saw with yesterday’s 5% drop in oil prices.

Here’s what you need to know – and how to benefit…

These ETNs Used to Bring Profits to Regular Investors

These ETNs were 3x “bull” and “bear” notes, respectively. That’s to say, the bullish one – VelocityShares 3x Long Crude Oil ETN (UWTI) – rises in value three times more than the New York benchmark for oil does, West Texas Intermediate (WTI).

Meanwhile, the bearish one – VelocityShares 3x Inverse Crude Oil ETN (DWTI) – moves up three times as fast as WTI falls (and vice versa).

Of course, both also lose value three times as fast as WTI moves against them. That makes both risky for regular investors, and are certainly not the kinds of securities you put in a portfolio hoping to send junior to college.

These are very volatile.

DWTI, the bearish ETN, was less capitalized, and I always regarded it as having too much risk for retail investors.

But here’s what’s really interesting about both UWTI and DWTI today.

While Credit Suisse dropped them from general trading and stopped providing daily trading values (thereby making them unusable for normal investors), the two notes remained in use.

For the individual investor, other less liquid clones replaced them. However, these have even greater volatility and insufficient trading volume, making them prone to extreme swings and unjustifiably excessive levels of risk.