Market Maker or some exchange we don't know of yet that is playing margin on Stamp (like coinarch on Finex).
Stamp does not offer margin as far as I know. Also, it seems to be giving away money with every trade. Odd behaviour for a market maker ...
Can you say more about coinarch on Finex? I don't know anything about that
This is getting OT, but could it be Stamp doing fee-less arb with other exchanges or allowing certain market makers to arb without fees?