Everest Capital, a hedge fund firm founded in 1990 that counted George Soros and Nelson Peltz as early backers, is closing six of its seven remaining hedge funds because of bad bets on the Swiss franc, according to CNBC, which cited a private letter sent to investors on Feb. 24.

Everest, which overall managed more than $3 billion at the end of December, had bets on the Swiss franc that backfired when the Swiss National Bank shocked markets in mid-January by removing a cap on the currency's value against the euro. That caused the Swiss franc to soar more than 30 percent versus the European currency, burning many investors in what had seemed like a low-risk trade.

The exact loss for Everest was unclear, but it was likely magnified by borrowed money, according to CNBC, which cited experts. A large portion of the fund's $830 million assets was wiped out, CNBC said, citing a person familiar with the situation.

Everest's decision to close the hedge funds comes after its largest fund, Everest Capital Global, suffered crippling losses in January and was shut down.

"I am saddened that our firm - which over the past 24 years identified and invested in hundreds of exciting investment opportunities in emerging markets - will cease to operate in its current form as a result of the events impacting the Global Fund," founder Marko Dimitrijevic wrote in the letter.

Dimitrijevic said in the letter that a "significant number of redemptions" had come in since the global fund collapsed, resulting in the decision to shut all but one fund.

The assets of the Miami-based firm were down to $2 billion by the end of January, according to separate investor materials, and presumably declined further over February, CNBC said. The funds will have most of their capital returned to investors by the end of March, according to the letter.

The remaining emerging markets fund managed $570 million at year end, meaning Everest will have lost at least 81 percent of its peak assets.