1. What is the Applicability of GST on the penal interest charged by a cooperative housing society from its defaulting members.
Answer: Its taxable and same is NOT covered under exemption entry No. 77 (c) of Notification No. 12/2017- Central Tax (Rate) as amended till date. So, if subject Co. operative society is registered under GST or required to be registered under GST (due to aggregate turnover exceeding prescribed limit, liability to pay GST under RCM etc.), GST is payable against such penal interest.
2. What is the Applicability of GST in case the monthly maintenance amount exceeds Rs.7500/- due to penal interest in case of default.
Answer: As explained above, applicability of GST against 'penal interest' has nothing to do with exemption entry No. 77 (c) of Notification No. 12/2017- Central Tax (Rate) as amended till date. So, GST is payable (i.e. if subject Co. operative society is registered under GST or required to be registered under GST) on 'penal interest' even when 'monthly contribution + penal interest thereon' does not exceed Rs. 7,500/-.
These are ex facie views of mine and the same should not be construed as professional advice / suggestion.