Comment on Notice under Section 139(9)? - Possible reason
No you cannot carry forward losses with ITR 4S. With ITR 4S, you can file with presumptive income, so if you have turnover of 10lks and you have made a loss, you show your income as 80k (8%) and hence not require an audit from a CA. If you are using ITR 4, you can show the loss and carry forward, but needs an audit.