Hmm, I'm not 100% sure, but in traditional options markets, I believe it was the exchange that backed the trade: http://www.options-trading-education.com/34/co

Hmm, I'm not 100% sure, but in traditional options markets, I believe it was the exchange that backed the trade: http://www.options-trading-education.com/34/counterparty-risk-in-option-trading/ http://www.options-trading-education.com/34/counterparty-ris... "In option trading on stocks risk management is handled by trading through standardized options contracts listed on futures and options exchanges. These markets provide accurate, up to date information, and back all contracts." If you're right, then the counterparty is not LedgerX, but some internet rando. Not sure that this would make me more complacent about counterpart risk.