The companies offered to sell additional single-equity derivatives assets, as well as giving the purchaser of those activities an option to access Eurex Clearing AG for single-equity derivatives. Eurex Group is Europe's largest derivatives exchange, jointly operated by Deutsche Boerse and SIX Swiss Exchange.

Although the exchanges did not specify what additional assets they would be prepared to sell, the original remedy package called for NYSE Euronext to sell its European single-derivatives activities except for those in Paris, Amsterdam, Lisbon and Brussels, where its German partner would give up its respective activities.

At the very least, the companies bought themselves some more time with the additional carrots, since the European Commission is now legally obliged to extend the deadline on its Phase two review from Jan. 23 to Feb. 9. The companies first notified their deal in Brussels on June 29.

Experts widely expect the companies to get the green light in Brussels, clearing what was seen as the biggest legal hurdle to the deal.

"A new offer and an extension are exactly what we expected, as without both the deal would have been dead," said Simon Holmes, a London-based partner with SJ Berwin LLP who oversees the law firm's EU and competition practice. "The parties are not out of the woods yet, but they are very much on a track towards clearance and getting the deal closed."

Investors also cheered the news, pushing Deutsche Boerse shares up 1.36% to €41.77 in late morning trading in Europe, for a market value of about €8.15 billion ($10.75 billion). NYSE Euronext shares closed at $27.24 Monday in New York, down 0.04% from Friday's close, for a market capitalization of $7.1 billion.

In a research note Tuesday, analyst Philipp Hässler of Equinet Bank AG in Frankfurt said that at first glance the revised remedies do not materially change the industrial logic of the deal, and that the earnings impact should be limited.

"We stick to our expectation that the takeover of NYSE/Euronext will finally be approved by the EU commission," he noted, leaving his rating on Deutsche Boerse stock unchanged at 'accumulate.' Nevertheless, he said there's still a 50% chance the deal will not go through.

The companies' initial remedy package included a pledge to give rivals access to their clearing activities.

In the revised package, the companies also pledged to license the Eurex trading system to a third party interested in launching interest rate derivatives, and they extended their clearing access remedy to trading in "innovative" equity-index and interest-rate derivatives.

"The revisions are designed to reflect the European Commission's feedback on the initial proposal, and thereby fully address the Commission's remaining concerns with the industrial and economic logic of the merger," the companies said.

They added that they will continue to work with the Commission to complete the transaction, which they expect to do early next year.