UPDATE 1-Axway shares surge on debut

* Axway's market value leaps to 379 mln eur

* Sopra shares down 4.1 pct

(Adds details, background)

PARIS, June 14 (Reuters) - French business-to-business specialist Axway Software's (AXW.PA) shares rose as much as 40 percent on their market debut on Tuesday as investors welcomed the spinoff from IT services firm Sopra (SOPR.PA).

Axway shares trimmed initial gains but were still up 28 percent at 23.80 euros by 0914 GMT, giving the company a market value of 384 million euros ($552 million).

The cost price of Axway shares had been set at 18.61 euros on Monday.

"For Sopra the deal is worth it," a Paris-based analyst said, speaking on condition of anonymity.

"But we don't know how Sopra's and Axway's capital will evolve and if it makes sense to keep a stake in both companies in the long term," he added.

Last week, Sopra shareholders approved plans to spin off and list 74 percent of Axway Software.

Sopra shareholders were to receive one Axway share and 3.92 euros for each Sopra share.

Shares in Sopra, which still controls 26.27 percent of Axway, were down 4.1 percent.

A first attempt to list the division in September 2010 had been blocked by investment fund Caravelle, Sopra's second-largest shareholder.

Axway's market debut follows the one of renewable energy specialist Global Bioenergies (ALGBE.PA) on June 9. (Reporting by Matthias Blamont. Additional reporting by Alexandre Boksenbaum-Granier; Editing by Mike Nesbit) ($1=.6955 euros)