Income tax

It depends upon your client. If he is a broker or commission agent and considers it his business the you can show it under PGBP and file ITR4. The client may also consider it as Other Source income but you may suggest him not to do so. In case no. of transaction are very low you can consider it Other Source Income and file ITR 1 or 2.

Agreed with CA Anil Agarwal, ITR 4 should be used if income is of regular nature.