The affix ṭhan comes in the sense of 'he lives thereby' after the words 1. vasna 2. kraya and 3. vikraya being in the Instrumental -3rd case in construction.,
This debars ठक् ॥ Thus वस्नेन जीवति = वस्निकः 'who lives by hire--hireling'. In the case of क्रय and विक्रय the affix is applied to the words separately, as well as to their compound. Thus क्रयविक्रयिकः, क्रयिकः, विक्रयिकः 'a trader'.,