By Giulio Piovaccari and Elvira Pollina

MILAN (Reuters) -Shares in Italy's top-flight soccer club Juventus rallied on Friday, after cryptocurrency firm Tether said it had become a minority shareholder, without disclosing the size of its stake.

Turin-based Juventus is controlled by Italy's Agnelli family through their investment company Exor, which holds a 64% stake in Italy's most successful club. The holding did not sell any shares to Tether, a spokesperson said.

On its website, Tether said the investment in the Milan-listed club had a "strategic" nature, as Juventus shares rose as much as 4.7% on heavy volumes, before paring gains and closing up 1.57% at 2.531 euros.

"Make Juventus Great Again," Tether CEO Paolo Ardoino wrote on X.

Juventus, which has been controlled by the Agnelli family for a century, had to raise around 900 million euros ($945.5 million) from its shareholders over the past six years in three separate cash call operations to beef up its balance sheet. It reported a loss of nearly 200 million euros in the financial year ending June 30.

Tether has emerged as a dominant force in the booming market for stablecoins, which are designed to maintain a constant value by being pegged to traditional currencies and offer users a way to move money between cryptocurrencies without exposure to price swings.

"Aligned with our strategic investment in Juve, Tether will be a pioneer in merging new technologies... with the well-established sports industry," Ardoino said in a company statement.

After dominating the Italian soccer landscape for nearly a decade until 2020, Juventus was hit by an accounting scandal linked to player trading and salary payments, whose consequences included a ban on European competitions last season.

The club, popularly known as the Bianconeri because of its black and white team jersey, currently ranks fifth in Italy's Serie A standings and is in a Champions League knockout phase playoff with PSV Eindhoven.

($1 = 0.9513 euro)