ProShares UltraShort Lehman 20+ Yr(ETF) logo Bluestein R H & Co. lifted its stake in ProShares UltraShort Lehman 20+ Yr(ETF) (NYSEARCA:TBT) by 15.0% in the 4th quarter, according to the company in its most recent Form 13F filing with the SEC. The fund ...
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