[USS Alaska]

When a privately held corporation borrows money, the loan is guaranteed by the owner of said corporation and that owner has their signature on it.

That only is true if it is a sub-Chapter S corporation.

There are thousands of private companies where the principals have no personal liability. In Western PA, two major retail outlets, both with sales over $5 BILLION, Giant Eagle and Sheetz are both private companies and the major share holders, are not liable for the corporate debt.

Either of these companies could declare bankruptcy and no owner/shareholder would lose a personal dime.

[biff]

Trump is playing games with his retoric about him not filing bankruptcy when he has rolled millions of his personal debts hidden under into the bankruptcies.

Your state laws may be different than others.