Company credit cards and owners

It depends on the circumstances. All owners of a corporation whether it's an S-corp or a C-corp offer their owners limited liability for the debts of the corporation. "Piercing the corporate veil" as it's called can be a nightmare 'cause it's determined by state case precedent. You can read more about this here, http://en.wikipedia.org/wiki/Piercing_the_corporate_veil if you're interested.

OVLG Attorney is correct if the debt is in the corporation's name it is pretty tough, but since most small businesses do not have their own credit rating, the banks make the owners personally guarantee the debt. In that case it is not a matter of "piercing the corporate veil". Once the business stops paying they can immediately start collecting from the owner.