Casualties mounted from the Swiss currency shock as a U.S. online brokerage said client debts threatened to push it out of compliance with capital rules and a New Zealand-based dealer went out of business.

FXCM Inc., a New York-based company that offers foreign exchange trading services over the Internet, said clients suffered significant losses when the Swiss National Bank's decision to abandon the franc's cap against the euro roiled global markets. Global Brokers NZ Ltd. said the impact on its business is forcing it to shut down.

"Due to unprecedented volatility in EUR/CHF pair after the Swiss National Bank announcement this morning, clients experienced significant losses, FXCM said in a statement dated Jan. 15. That "generated negative equity balances owed to FXCM of approximately $225 million."