Shares of Nokia Oyj, the Finnish mobile-phone maker, rose as much as 6.2 percent in after-market U.S. trading Wednesday on a report that Microsoft Corp. discussed acquiring the company’s device business.

Nokia’s American depositary receipts rose as high as $4.09 after the Wall Street Journal reported on the talks. According to the newspaper, the two sides made “significant progress” on a plan to combine Microsoft with Nokia’s phone business, though the discussions have since faltered. The shares had closed at $3.85 in regular New York trading earlier in the day.

Nokia, once the dominant company in the mobile-phone industry, has struggled to win back market share from Apple Inc. and Samsung Electronics Co. That’s left investors pinning their aspirations to a takeover deal. Nokia’s ADRs rose almost 5 percent Tuesday after a report that Chinese telecommunications business Huawei Technologies Co. may be interested in acquiring the entire company.

Nokia and Microsoft already have a close partnership, with the Espoo, Finland-based company relying on the U.S. software maker for operating-system technology. Nokia introduced the Lumia 925 last month, which runs on Microsoft’s Windows 8.

Frank Shaw, a spokesman for Redmond, Washington-based Microsoft, declined to comment. Chris Hollis, a U.S.-based spokesman for Nokia, didn’t immediately respond to a request for comment.