Liquidator notification triggers provisional tax estimate and director joint liability for unrecovered GST and penalty exposure. The liquidator must notify the Commissioner of appointment, after which the Commissioner will inquire and notify an amount sufficient to provide for tax, interest or penalty likely payable by the company; if tax liabilities cannot be recovered from a private company, every person who was a director during the relevant period is jointly and severally liable unless he proves that non recovery was not due to his gross neglect, misfeasance or breach of duty.