Thete's a big difference between a private firm and a private equity firm.
Private firm - no public trading of stocks.
Private equity - a business model created by syndicates that borrow money to buy companies, saddle the companies with that borrowing, demand a quick return (-> layoffs, selloffs, and wage cuts), then bankrupt the company when all the value and productivity have been extracted.
Crucially the money which is never repaid is not borne by the banks that put that money up front, they chop it up and sell it off with other things so nobody even knows who loses the money.
Private firm - no public trading of stocks.
Private equity - a business model created by syndicates that borrow money to buy companies, saddle the companies with that borrowing, demand a quick return (-> layoffs, selloffs, and wage cuts), then bankrupt the company when all the value and productivity have been extracted.