Joint and several liability for partners ensures firm-level tax, interest and penalty remain collectible despite discontinuance or reconstitution. When a firm, association of persons or HUF discontinues, tax, interest and penalty up to discontinuance may be determined as if discontinuance had not occurred, and every partner or member at that time is jointly and severally liable for payment of those liabilities; similar joint and several liability attaches to partners or members before and after reconstitution for pre-reconstitution dues, and the same rules apply on dissolution or partition. A Limited Liability Partnership is treated as a firm.