PORTLAND – After being dropped by two insurers, York-Cumberland Housing Development Corp. scrambled to line up someone to provide property and liability coverage on the agency’s 830 apartments.

The agency finally found a one-year deal that will increase its premium by more than 80 percent, from $194,000 to $365,000. The coverage, which is not as comprehensive, also raises the agency’s deductible from $2,500 to $10,000.

“We’re feeling very helpless,” said Dana Totman, York-Cumberland Housing’s executive director. “To be dropped and then to face such outrageous increases creates a very real feeling of helplessness.”

The cost of commercial property insurance in Maine has soared by up to 100 percent in the past six months, prompting concerns that such increases will inhibit investment in new rental housing at a time when the region faces an acute housing shortage.

“There’s already enough risk factors out there,” said Jamie Whelan, regional manager for Princeton Properties, Portland’s largest private landlord, with 477 apartments. “When you add rising insurance costs, that certainly could have a calming effect on people’s willingness to do housing.”

The prospects for relief from rising insurance costs appear unlikely as observers predict double- and triple-digit increases for at least two more years.

Many multifamily underwriters have abandoned the market after experiencing losses on claims for several years. The fewer number of carriers combined with the monumental losses related to Sept. 11 and other calamities – floods in Texas and earthquakes out West – has given the remaining underwriters reason to increase their rates and deductibles.

Alessandro Iuppa, Maine’s superintendent of insurance, said that with the slump on Wall Street, insurers can no longer rely on their investments to compensate for their losses.

No one seems to know if the higher rates are the new reality, or if costs will come down once the stock market improves and insurance companies are again making money on their investments.

Thomas Deveaux, executive vice president of Banknorth Inc.’s insurance group, said the consolidation of carriers combined with the bear market has made insurers even more risk averse.

“They’re looking at everything with a fine-tooth comb,” Deveaux said. “They’re saying, ‘Can we make money on this?’ If the answer’s no, they’re flatly denying it. There’s certainly a limited appetite right now for multifamily housing.”