SINGAPORE, July 28 (Reuters) - Bitcoin broke above $40,000 on Wednesday and headed for another attempt at breaking from its monthslong range as short sellers bailed out and traders drew confidence from recent positive comments about the cryptocurrency by high-profile investors. Bitcoin was last up 1.7% at $40,149 while rival cryptocurrency ether rose 1% to $2,328. Bitcoin is within a whisker of rising through its 100-day moving average.