Orange juice tumbled from a four- year high after ICE Futures U.S. boosted the amount of cash that traders must deposit for speculative positions by 95 percent.

Prices soared 17 percent in the past two days on concern that a freeze in Florida damaged citrus groves and that a U.S. probe of a fungicide used on fruit in Brazil, the world’s largest orange grower, may limit imports. The New York exchange almost doubled the initial margin for a speculative contract to $5,040 from $2,590. As of yesterday, each contract for 15,000 pounds (6.8 metric tons) of juice was valued at $31,162.50.

“Margin calls will force some people out of the market,” Sterling Smith, an analyst with Country Hedging in St. Paul, Minnesota, said in an e-mail.

Orange-juice futures for March delivery slumped 4.9 percent to $1.975 a pound at 11:25 a.m. on ICE in New York. A close at the price would mark the biggest drop for a most-active contract since Aug. 10.

Yesterday, the contract surged by the exchange limit for a second straight day. Prices advanced 11 percent, the most in five years, to $2.0775, the highest since March 2007. The record was $2.094 on Dec. 7, 2006.

“The market got overdone yesterday,” Jack Scoville, a vice president at Price Futures Group in Chicago, said in a telephone interview.

The U.S. Food and Drug Administration said on Jan. 9 that it will investigate the use of carbendazim on orange trees in Brazil, which supplies about 25 percent of the juice consumed in the U.S. Florida is the second-biggest producer.

Inventories, USDA

Slumping U.S. inventories already had helped send orange- juice futures up almost 39 percent in New York since the end of September, just as frigid weather in Florida last week also trimmed the state’s crop outlook, according to MDA Information Systems. Stockpiles at facilities monitored by ICE tumbled 58 percent to 22.785 million pounds as of Jan. 10 from a year earlier, exchange data show.

“While it will be turning cooler in Florida this weekend, temperatures are expected to remain above frost levels in the citrus areas,” Kyle Tapley, a meteorologist at Gaithersburg, Maryland-based MDA, said in an e-mail today. “Fairly dry weather should continue to favor late citrus harvesting” in the state, he said.

The U.S. Department of Agriculture will release an update on Florida’s crop tomorrow. Last month, the Washington-based agency increased by 2 percent its production forecast to 150 million boxes because favorable weather aided fruit size. A box weighs 90 pounds, or 41 kilograms.

“We have a USDA report tomorrow, and some people are getting out,” Scoville said.