Opel Chairman Nick Reilly said General Motors was very satisfied with progress at Opel, but stopped short of commenting on whether the U.S. auto maker had put the European unit up for sale.

General Motors is very happy with the fact that Opel/Vauxhall is ahead of plan in terms of restructuring, Reilly said in a written statement released following a meeting of the supervisory board, which is akin to a board of directors.

But Reilly failed to quash rumors that GM was mulling a sale of the European brand, saying GM does not comment on speculation.

The statement said GM would not deviate from this policy of no comment, particularly since it had a responsibility toward shareholders and needed to comply with the rules of a stockmarket-listed company.

A GM spokesman in Detroit declined to comment beyond the statement out of Germany.

Rumors GM was in talks to sell European carmaker Opel surfaced earlier this month, but a German newspaper reported that GM Chief Executive Daniel Akerson has reassured Opel that it was not in talks to sell it.

GM Europe posted a profit in Europe during the first quarter, and Opel increased monthly market share for the seventh month in a row on a year-on-year basis, Reilly said.

Opel remains a high-cost player in a low-growth region, in a segment dogged by cutthroat competition, leading to speculation of a sale or labor concessions by its workers.

However, neither a sale or a quick fix to return to sustained profitable growth are easily achievable, analysts and experts say.

The U.S. automaker dropped plans to sell Opel in 2009 after months of negotiations and embarked on a drastic restructuring to get the unit, which lost $1.6 billion last year, back on track.