Stablecoin co Circle quadruples from IPO price

** Shares of stablecoin firm Circle Internet continue to surge and are up 19.6% at $128.80 premarket, more than quadruple their IPO price

** CRCL shares on Fri closed up ~29% at $107.70 in their second day of trading following blowout debut on Thurs after $1.05 bln offering priced at $31

** On a fully diluted basis, New York-based firm notched roughly $28 bln valuation as of Fri

** Meanwhile, crypto exchange Gemini, run by billionaire twins Tyler and Cameron Winklevoss, on Fri said it confidentially filed for a U.S. IPO, in hopes of capitalizing on renewed market momentum in digital assets

** Last month, the addition of Coinbase to the benchmark S&P 500 was seen as a watershed moment for the industry