BlackRock makes its debut while three others expand their offerings initially designed for professional investors.

A group of 21 exchange-traded notes (ETNs) on Bitcoin or Ether went live on the London Stock Exchange (LSE) on Monday, allowing retail British investors to access the digital assets for the first time.     BlackRock’s iShares Bitcoin ETP (IB1T) is a brand new listing on the bourse, seven months after its debut in multiple European markets .  Meanwhile, WisdomTree, 21Shares and Bitwise have broadened the access of their lineup to retail investors, which went listed on