US nonprofit Bon Secours Mercy Health is in talks to buy a controlling stake in Surgery Partners, a surgery center operator, for $6 billion, taking into account $3.5 billion in debt. As part of the deal, the investment fund Bain Capital will keep its stake in the company at about 40%. The acquisition will allow Bon Secours to take over 176 clinics in 30 countries and accelerate the expansion of care outside the hospital.