The first U.S. bitcoin futures-based exchange-traded fund started trading this week and showed positive results. The ProShares Bitcoin Strategy ETF closed up 2.59% at US$41.94 on its first day of trading. The launch of the first-ever US bitcoin futures ETF sent bitcoin to a six-month high and could boost investment flows into cryptocurrencies. Bitcoin has risen around 45% this month in hopes that the advent of U.S. bitcoin futures ETFs will spur billions of dollars of investment in the sector. Crypto ETFs have launched this year in Canada and some European countries amid surging interest in digital assets. However, the US regulator has yet to approve a spot bitcoin ETF.