The Manhattan apartment market hit the pause button during the second quarter with sales and prices flattening out despite a spurt of record deals, according to new data.

A series of market report released Tuesday showed that sales and prices hovered near levels reported during the 2011 second quarter, despite an improving local economy and strong interest from international buyers.

The third quarter started with the disclosure that the most expensive condominium currently on the market—a huge apartment on the 75th and 76th floors of One57 on West 57th Street that was listed for $115 million— has found a buyer, a person familiar with the deal said Monday.

The condo has six bedrooms, and a large glassed in terrace with more than 13,500 square feet of space, according to the condominium plan. The contract price wasn’t disclosed, but brokers said it was likely below another the price of another huge duplex in the building on the 89th and 90th floors that was in contract for a record-setting price of more than $90 million.

Gary Barnett, president of Extell Development Co., which is putting up the 1,004-foot tower across from Carnegie Hall, declined to identify the buyers of the huge apartments. But he said rumors that the buyers were from the former Soviet Union or the Middle East were incorrect.

“Neither is on the right continent,” Mr. Barnett said, “So they have another five guesses to go.”

The market reports tell a less-swashbuckling picture of overall conditions in Manhattan. Despite an improving local economy, reports of bidding wars for expensive apartments and falling inventory of apartments on the market, the report shows market showed no dramatic moves.

One particularly pessimistic report by Prudential Douglas Elliman showed that the number of sales were just about flat, down 0.1%, from the same quarter in 2011, while median price of an apartment prices fell slightly by 2.5%. Several other reports showed slightly higher prices and sales.

The Elliman report, prepared by Jonathan Miller, an appraiser and president of Miller Samuel Inc, found that median prices of co-ops were down by 5% while median condominium prices were up by 2.8%, compared with the year-earlier quarter.

The report put the average price for a Manhattan condominium at $1.408 million, down 3.2% from the same quarter last year, but up 5% from the first quarter.

Mr. Miller said he viewed the overall market as “stable” and attributed part of the median price decline to a pickup in sales of lower-priced studios and one-bedroom apartments, due to a drop in mortgage rates and rising rents.

A falling supply of apartment on the market is usually a positive indicator for a market. But Mr. Miller said this time it might be different both in New York and around the country.

He said supply is falling, not because of market forces, but because sellers have been reluctant to list their apartments on the market. He said many would-be sellers don’t have enough equity to trade up to a larger apartment or lack enough confidence in the economy to do so.

Buyers remain price sensitive and worried about the economy, said Hall F. Willkie, the president of Brown Harris Stevens. “Sellers need to understand that prices need to be justified,” he said.

Other analysts were more positive. “With both the average and median prices holding steady, it is clear that we have an active market at all price points,” said Jim Gricar, general sales manager of Halstead Property.

Sofia Song, vice president of research at StreetEasy.com, pointed to a sharp increase in contracts signed during the second quarter. She said contracts listed as signed in May were up 46% compared with the previous May. In June they were up far less, by 5% compared with the previous June.

At One57, there had been persistent rumors that the prime minister of Qatar had signed a contract to buy a block of apartments, but this was disputed by several brokers.

“We feel perfectly capable of dealing with high service requirements without impinging on any other resident,” Mr. Barnett said. “We would be very happy to have the prime minister of Qatar in our building.”