When optionsellers blew up, the clients not only lost 100% of their invested money but owe money to the broker as well. In other words, clients lost more than 100% of their money. The risk is unlimited. https://www.elitetrader.com/et/thre...er-do-to-blow-up-his-fund-and-clients.327102/ I never know such a thing can happen as an investor in professional funds. I always assume risk is limited to 100% loss which is bad enough as a worst-case. I didn't know risk can be unlimited. This is certainly a risk that all clients must be aware of. What are the kind of funds or fund structure to be aware when investing in professional funds to avoid this kind of unlimited risk? Do clients of CTA face such a risk? When Amaranth and LTCM blew up, did their clients lose more than 100% of their losses?