Cost-cutting helped NYSE Euronext beat earnings expectations, and the transatlantic exchange operator announced the sale of a big stake in its U.S. derivatives exchange.

The parent company of the New York Stock Exchange said underlying costs dropped 10 percent in the third quarter and forecast that expenses this year would be considerably below its previous estimate.

Analysts said the European launch of NYSE Liffe Clearing helped drive third-quarter earnings, despite an overall trading volume drop and lower cash equities market share.

Recent results have been a step in the right direction as management continues to realize synergies and control expenses, Credit Suisse analysts said in a research note.

NYSE Euronext said it was selling the stake in NYSE Liffe U.S. to Goldman Sachs , Morgan Stanley , UBS AG , hedge fund Citadel Securities, and Getco, the big electronic maker, to accelerate the growth of its U.S. futures exchange.

The bourse will remain the biggest shareholder of the U.S. part of NYSE Liffe, which offers trading on gold and silver futures and equity indexes, and plans to expand into U.S. interest rates.

The venture, which could challenge derivatives giant CME Group Inc , adds to a growing list of exchange partnerships with banks and other big market players, as U.S. and European regulators push more standardized over-the-counter derivatives through transparent markets and clearinghouses.

They're partnering to grow the business until it's profitable. So although it may be frustrating from an investor perspective, it's better not to be going it alone, said Edward Ditmire, analyst at Fox-Pitt Kelton.

They're treating U.S. futures and Amex options (another joint venture) like a new product, and no new products are working right now, he added.

NYSE Euronext said third-quarter net revenue was down 13.8 percent to $624 million, hurt by a fall in global cash equities volumes and price cuts in the European and U.S. cash businesses.

Net earnings declined 28 percent to $125 million.

Excluding one-time items, the company earned $138 million, or 53 cents per share. Analysts on average had expected 46 cents per share, according to Thomson Reuters I/B/E/S.

NYSE Euronext, like rival Nasdaq OMX , has been under pressure from younger trading venues but has adopted new technology to speed up global trading. Its matched market share of NYSE-listed companies was 35.5 percent in the quarter, down from 42.5 percent last year.

However, its overall U.S. market share rose from July through September, and CEO Duncan Niederauer said in a statement the bourse's core businesses continued to stabilize.

NYSE Euronext runs exchanges in Paris, Amsterdam, Brussels and Lisbon, following its 2007 acquisition of Euronext. It is also a key player in the ongoing U.S. debate over dark pools, high-frequency trading, and other market structure issues.

Shares of the company rose 1.6 percent to 18.57 euros in Paris and were up 1.5 percent at $27.99 in U.S. premarket trade.

(Reporting by Daisy Ku and Jonathan Spicer; Editing by Rupert Winchester and John Wallace)