ProShares Ultra Dow30 (NYSEARCA:DDM – Get Free Report) saw a significant growth in short interest during the month of January. ProShares Ultra Dow30 Stock PerformanceShares of DDM remained flat at $58.82 during midday trading on Wednesday. Get ProShares Ultra Dow30 alerts:Institutional Investors Weigh In On ProShares Ultra Dow30A number of large investors have recently added to or reduced their stakes in the stock. About ProShares Ultra Dow30The ProShares Ultra Dow30 (DDM) is an exchange-traded fund that is based on the Dow Jones Industrial Average index. See AlsoReceive News & Ratings for ProShares Ultra Dow30 Daily - Enter your email address below to receive a concise daily summary of the latest news and analysts' ratings for ProShares Ultra Dow30 and related companies with MarketBeat.com's FREE daily email newsletter.