Investors are flocking to an inverse Treasury ETF to position for higher yields and lower bond prices.

“Yesterday we saw literally an explosion of call buyers in leveraged inverse product ProShares UltraShort 20+ Year Treasury Bond (NYSEArca: TBT) as more than 100,000 call options exchanged hands,” Paul Weisbruch at Street One Financial said in a note Friday.

“We have pointed out institutional piling into inverse (bearish) Treasury Bond products for some time now, and with equities stabilizing and iShares Barclays 20+ Year Treasury Bond (NYSEArca: TLT) falling precipitously of late … the TBT trade has become even more popular with call buying in TBT as well as TLT put buying with similar motivations,” he said.

Yields on the 10-year Treasury note climbed above 1.7% on Thursday after bottoming out below 1.4% in July.

The recent pullback in TLT suggests the incredible amount of fear built up in markets may be unwinding.

Earlier this week, the Treasury ETF dropped below its 50-day simple moving average for the first time since April.

Nervous investors have herded into Treasury bonds on concerns over the Eurozone debt crisis and a sluggish U.S. economy. As a result, Treasuries are seen as one of the most overcrowded trades in the market. [Treasury ETFs: Reverse Flight to Safety?]

ProShares UltraShort 20+ Year Treasury Bond

Full disclosure: Tom Lydon’s clients own TLT.