Nokia Corp and Siemens AG failed to secure a deal for investors for a controlling stake in their unprofitable joint venture, The Wall Street Journal reported on Sunday.

The companies, which could not be immediately reached for comment, are now weighing investing more money in the venture, which is called Nokia Siemens Networks (NSN), the newspaper said in its electronic edition.

Talks to sell a controlling stake in the venture, which is the world's No. 2 maker of wireless-networking gear, to a consortium that includes private-equity firms Gores Group LLC and Platinum Equity LLC are not expected to succeed, the newspaper said.

Any potential investor would need to see some light at the end of the tunnel with regards to profitability for NSN, Earl Lum, chief of telecom gear industry research firm EJL Wireless, told Reuters.

In light of the fact that the company has only recorded profitability in two quarters since 2007, we believe that investors are uncomfortable with the current valuation that Nokia and Siemens are seeking for NSN, Lum said.

Nokia and German industrial group Siemens merged their telecom equipment businesses on a 50-50 ownership basis in 2007 in a six-year deal, hoping to quickly reach double-digit margins, but the venture has struggled to make a profit.

Nokia and Siemens each owns half of the business, but Nokia holds four of the seven board seats. With Nokia Siemens Networks losing nearly $1 billion last year, the sale of a majority stake would have let Nokia eliminate a major drag on its financial results, the newspaper said.

Siemens has been frustrated with its partner's inability to find a solution and Siemens could take control of the joint venture, the newspaper said.

Private equity firms KKR and TPG still could strike a deal that would involve them taking a small stake in Nokia Siemens, the newspaper said.

The Financial Times reported earlier this month that the two private equity firms had decided against bidding for a stake in the venture after failing to agree on price and level of control.

Earlier this month, Nokia said it was in talks with multiple parties about its stake in Nokia Siemens Networks.

(Reporting by Jessica Hall; Editing by Leslie Adler)