Qatar Sports Investments (QSI) became the Parisian outfit's sole owner more than a decade ago and the club has won the Ligue 1 title nine times since then.
Arctos has already invested in more than 20 professional sports organisations around the world.
According to a source close to QSI, the firm has acquired a 12.5 per cent stake in the club, which has a total value of €4.25 billion (£3.6 billion), putting Arctos' investment at €530 million (£455 million).
"The investment from Arctos will go towards growing PSG's operations and also supporting the club's strategic real estate initiatives, including relating to its stadium and the future development phases of PSG's world-leading training centre at Poissy in suburban Paris," the club said.
"Arctos will also provide strategic services, expertise and insights aimed at helping the club achieve its ambitions."
These services would include sustaining growth, continuing the club's international expansion into new markets, including North America, "engaging new and existing fans" across the world and "collaborating to explore sports investment opportunities around the globe", they added.
PSG said the firm would have no influence over on-field matters or the squad that includes France World Cup winner Kylian Mbappe and is coached by Spaniard Luis Enrique.
Nasser Al-Khelaifi, chairman of QSI and PSG, described the acquisition as "an important milestone in Paris Saint-Germain's history".
In November 2022, El-Khelaifi told the Financial Times he was in discussions with numerous investors to sell 15 per cent of the club.
Despite domestic success, PSG have failed to win the Champions League, finishing runners-up in 2020.
Their next game is Saturday's home Ligue 1 match with Nantes before Wednesday's crucial Champions League group stage fixture at Borussia Dortmund.
Off the field, there is a cloud hanging over the future of PSG's Parc des Princes home as the club is having difficulty discussing with the stadium's owner, the city of Paris.
They are also expected in January to put forward their dossier for buying the Stade de France as an alternative, if conversations with Paris authorities fail.
Arctos, which was founded in 2019 and has its headquarters in Dallas, Texas, has invested in the NBA's Golden State Warriors, MLB's Chicago Cubs as well the Fenway Sports Group, which owns the English Premier League club Liverpool and US baseball franchise Boston Red Sox.
