He may have formed a holding company etc to protect himself against creditors, but chances are any dealings with the bank would have been on the condition of a personal guarantee from Mark himself, as he is likely the only shareholder and effectively the holding company is just to protect himself. The banks aren't stupid enough to accept that, so he'll be liable to them.
Suppliers etc won't be paid by Mark though, if they are it'll be pennies.
He wasn't the only investor in the company. He said as much in the last episode - someone had invested the year before, which pulled the hotel back from the brink then, when he was 15 says away from closing it completely.