NEW YORK – Wright Express Corp., a Maine-based provider of fleet-management services, fell flat in Wednesday’s sole initial public offering, failing to drive interest despite pricing the deal below expectations during a busy month for new stocks.

Wright, with headquarters in South Portland, sold 40 million shares at $18 apiece – below the estimated $19 to $21 range – to raise $720 million in proceeds. All of the shares were sold by parent Cendant Corp., an operator of hotels, rental-car companies and travel services.

Wright shares, trading on the New York Stock Exchange as “WXS,” opened at $17.50 and closed at $17.10, down 90 cents, or about 5 percent. It was the sixth most active issue on the Big Board with about 16.4 million shares changing hands.

J.P. Morgan, Credit Suisse First Boston and Merrill Lynch co-managed the offering. Wright’s underwriters have the option to buy up to 6 million additional shares to cover overallotments.