Juventus' share price surged nearly 19% as shareholders cheered the move to set up a rival to UEFA's established Champions League, Europe's most prestigious club competition.
Shares in Manchester United rose 9% after opening on the New York Stock Exchange.
The Super League, financed by U.S. bank JP Morgan, heralds the prospect of bigger and more stable revenue streams for the club's billionaire owners.
But the news was condemned by football authorities, fans groups and by political leaders who argue the move is driven solely by money and undermines the integrity of the sport by creating a closed shop for elite clubs. Current competitions require all teams to qualify.
Intesa Sanpaolo analysts estimate a Super League would fetch more in TV rights than the roughly 2 billion euros ($2.4 billion) the Champions League earned per year in the seasons 2018-21, and would be split among just 20 clubs.
"Ticket sales, sponsorship and merchandising could benefit too, considering the quality of matches and the large audience of these clubs," analysts at the Italian bank said.
As well as United, Premier League clubs Liverpool, Manchester City, Chelsea, Arsenal and Tottenham Hotspur have signed up to the plans.
From Spain, Barcelona, Real Madrid and Atletico Madrid are joining. AC Milan and Inter Milan make up the trio from Italy along with Juventus.
The Super League aims to have 15 founding members and a 20-team league with five other clubs qualifying each season.
The announcement marks a new phase in the bitter battle for soccer and its multi-billion dollar revenues -- an infuriated UEFA said participating clubs and players could be banned from all of its competitions and the World Cup.
Some analysts think the announcement may prove a ploy by the big clubs, some of them highly indebted, to extract more money from existing competitions after a year in which the COVID-19 pandemic has hammered their revenues.
"Whether it's Super League or not, the signal is that the big clubs want to 'renegotiate' with UEFA the proceeds, so it's definitely something that stirs the waters...," said Angelo Meda, head of equities at Banor SIM in Milan.
"I doubt that they have moved like this and will give in, something will be granted."
Shares in soccer clubs Ajax, Olympique Lyon AS Roma, which are not part of the Super League, rose marginally or were down slightly in late European trading.
Firms with broadcasting rights for existing competitions also face a major hit from a new Super League.
Citi analysts said the "clear implication" was "a significant diminution of the value of the rights" for the existing Champions League which would either be "made entirely redundant or continue without the participation of some/most of the most important and valuable clubs".
Broadcaster BT, which pays hundreds of millions of pounds a year to show the Champions League, English Premier League and National League matches, condemned the breakaway plan.
France's Vivendi, Spain's Telefonica and Sweden's Telia and Amazon and Comcast in the United States are among the other listed companies holding Champions League distribution rights.
Juventus shares https://fingfx.thomsonreuters.com/gfx/mkt/yzdvxbqeevx/Juventus.JPG
($1 = 0.8317 euros)
(Writing by Tommy Reggiori Wilkes, additional reporting by Julien Ponthus; Editing by Thyagaraju Adinarayan and Alison Williams)
By Giancarlo Navach and Danilo Masoni