Nasdaq OMX Group, long on the hunt for a partner, has ramped up its consideration of strategic options ranging from a joint venture to a sale, according to people familiar with the matter, as rival NYSE Euronext moves ahead with a merger that will form an even-bigger competitor.

Recently, Nasdaq held preliminary talks with Carlyle Group about a deal to take the exchange company private, according to people familiar with the discussions. Nasdaq also has had talks with people at CME Group, some people said, including about partnerships around technology and indexes, one of the people said. It isn't clear if the conversations contemplated a larger deal.