By Jose Elías Rodríguez and Andrés González
MADRID (Reuters) - Spanish utility Iberdrola (MC:IBE) is becoming increasingly concerned about the way German group Siemens (DE:SIEGn) is managing the Spanish-based wind power joint venture Siemens Gamesa (MC:SGREN), two people with knowledge of the matter said.
Alarmed by a second profit warning last week, Iberdrola representatives called for significant changes at the top of Siemens Gamesa during a board meeting on Friday, the sources said.
"It is not possible to announce two profit warnings in less than three months without consequences in the top management," one of those sources said.
They said Iberdrola's demand remained informal at this stage.
Iberdrola, Siemens and Siemens Gamesa declined to comment.
Siemens has a controlling stake of 59 per cent in Siemens Gamesa, which vies with Denmark's Vestas as the world's biggest wind turbine maker. However, Iberdrola has a say in certain corporate governance matters thanks to a shareholder pact signed when Siemens Wind agreed to merge with Gamesa in June last year.
Iberdrola is the second-largest shareholder in Siemens Gamesa with an 8 percent stake.
Since the merger took place last April Gamesa Siemens' shares have tumbled 44 per cent as it repeatedly cut its forecasts for profitability.
The wider industry has suffered from stiff competition and a winding down of state subsidies, but Danish rival Vesta's (CO:VWS) shares have fallen by just 4.9 percent during the same period.