LONDON: Bitcoin hovered just below its record highs on Wednesday (Oct 20) and the first US bitcoin futures-based exchange-traded fund (ETF) looked set to open firmer after surging on its debut on Tuesday.The world's leading cryptocurrency was at US$64,257 at 12.36pm GMT, modestly higher on the day and within a short jump of the all-time high of US$64,895.22 it hit on Apr 14 this year.It reached as high as US$64,499 on Tuesday, late in the US session.Tuesday was the first day of trading for the ProShares Bitcoin Strategy ETF - a development that market participants say is likely to drive investment into the digital asset.The ETF closed up 2.59 per cent at US$41.94 on Tuesday, with around US$1 billion worth of shares trading hands on