** Trading platform Webull's BULL.O shares jump 137.8% to $31.51 in premarket trading
** BULL closed up 10.2% at $13.25 on Friday in Nasdaq debut after completing merger with blank-check firm SK Growth Opportunities Corporation
** About 3.9 million BULL shares changed hands on Friday, per data compiled by LSEG
** BULL has ~471.1 million outstanding shares for $6.24 billion market cap as of last close, per LSEG
** Founded in 2016 by Alibaba veteran Anquan Wang, BULL's trading platform allows users to invest in stocks, exchange traded funds, cryptocurrencies and more
** BULL launched in the U.S. in 2018 and has since expanded to 15 regions covering Asia Pacific, Europe and Latin America
** St. Petersburg, Florida-based BULL caters to more than 23 million users globally
(Reporting by Arasu Kannagi Basil in Bengaluru)
((ArasuKannagi.Basil@thomsonreuters.com;))