Fleet-Norstar Financial Group announced a first-quarter loss of $98 million Thursday, placing the long-prosperous bank on the list of institutions adversely affected by New England’s sluggish economy.

The loss was the first recorded by Fleet since 1974. Like its sister institutions in New England, Fleet’s loss resulted from bad loans in the commercial real estate market. The bank, which is based in Providence, R.I., and Albany, N.Y., listed non-performing assets of $928 million. Of that total, $552 million was in commercial real estate.

The quarterly results, normally announced in mid-April, had been on hold pending an investigation by state and federal regulators of the bank’s loan portfolio.

Bucking the trend toward losses, the bank’s Maine affiliate, Fleet Bank of Maine, turned a profit of $3.8 million in the first quarter, down from $4.9 million in the fourth quarter of 1989. Roger Castonguay, the Maine bank’s president, called the profit “respectable.”

John McGinn, the Bangor-based senior executive vice president at Fleet, said that there would be no branch sales or layoffs as a result of woes at the parent bank.

According to McGinn, the only way the Maine bank has been affected has been through participation in Fleet’s sale of some credit-card operations, and a change in the investments making up the bank’s pension plan.

Fleet’s first-quarter results included $90 million of non-recurring income from the sale of the credit-card business and changes in the pension funding. This income reduced the impact of the bad real-estate loans.

McGinn said that $10 million of the one-time income came from Maine. He said that the credit-card business of people not otherwise doing business with Fleet was sold. And annuities were purchased from an insurance company to take care of the pensions. The balance in the previously overfunded pension plan then was put in the special, one-time, $90 million income account.

A month ago, Fleet said that its non-performing loans probably would be about $600 million. But in response to the crisis at savings and loan institutions, state and federal regulators are expanding their definition of non-performing loans.

“Of the $928 million, $412 million of those assets are performing assets right now, (in the sense that) they either are truly current or less than 90 days past due,” said John W. Flynn, Fleet’s chief financial officer.

McGinn explained that regulators now count as non-performing certain loans that are between 30 and 90 days past due. Previously, non-performers were loans more than 90 days past due. And some real estate loans that are being routinely paid are counted as non-performing if the value of the collateral asset falls below the value of the loan.

McGinn was quick to point out that Fleet’s woes were relatively small compared with other New England banks. For example, non-performing loans at Bank of New England and Bank of Boston are more than twice the level recorded by Fleet.

Fleet’s earnings report also indictates the relative sluggishness of the New England economy. For example, Norstar Bank of Upstate New York, the financial group’s lead bank outside of the region, earned a first-quarter profit of $17 million, up $2 million.

Fleet officials don’t expect additional problems. “Numerically our non-performing assets are lower than others in the region,” Flynn said. “Our equity capital is higher than others in the region and over the last two years our earnings have been substantially higher. Obviously, we believe we are far more diversified than almost anybody in the country.”

Despite the loss, Fleet’s board of directors declared a regular quarterly dividend of 35 cents per share on its common stock. The dividend will be payable July 1, 1990, to stockholders of record on June 15, 1990.

And perhaps surprisingly, the stock market responded to the news of the Fleet loss by increasing the value of its stock to $19 1/4, up 1/2. With rumors of the loss circulating for some weeks, the loss already had been discounted by the market, said Gerard Cassidy, a Portland-based banking analyst for Tucker Anthony & R L Day. Fleet stock traded for about $29 a share last year. Its low value of $18 5/8 was recorded Wednesday.

“The market is a game of expectations, and the loss had been expected,” Cassidy said. He agrees with Fleet officials that the bank is in relatively good shape.

“It’s in a class by itself compared with other New England banks,” Cassidy said.

Cassidy thinks that Fleet still is a good long-term investment. But in the short term, none of the region’s bank stocks are a good buy, he said.