Director liability for unpaid GST: joint and several obligation unless director proves non-recovery not caused by gross neglect or misfeasance. Directors of a private company are jointly and severally liable for unpaid tax, interest or penalty where recovery from the company is not possible, unless the director proves the non-recovery is not due to gross neglect, misfeasance or breach of duty. Upon conversion to a public company, that joint and several liability does not apply to former private-company directors for liabilities of the private period that remained unrecovered before conversion, but any personal penalty imposed on a director remains payable.