币界网报道:Asset management company Calamos announced the launch of three Bitcoin exchange-traded funds designed to provide investors with downside protection exposure: Calamos Bitcoin Structured Alt Protection ETF, Calamos Bitcoin 90 Series Structured Alt Protection ETF and Calamos Bitcoin 80 Series Structured Alt Protection ETF. These three ETFs plan to invest in US stock benchmark indices and Bitcoin, and are expected to start trading on July 8.