The purchase encompasses Volkswind's 31 wind farms with a total of 154MW, and a substantial project pipeline in Germany and France.
Approximately 460MW is already permitted and another 2,500MW of capacity is at various stages of the permitting process, Axpo said.
"Axpo is strengthening its position in the area of renewable energies and entering into the market for construction and development of wind power plants in Germany and France. These are our key markets when it comes to wind farm projects," an Axpo spokesperson said.
The cost of the deal was undisclosed but is subject to relevant competition approval. The company will continue to trade under the Volkswind name.
Axpo thereby takes on a substantial onshore wind portfolio to complement its 1GW Limmern hydro pumped storage plant, currently under construction in Switzerland, and electricity trading activities.
Axpo owns 174MW of onshore wind capacity and a 24.1% stake in the Global Tech 1 German offshore project currently being commissioned in the North Sea.
Founded in 1993, Volkswind now has 60 employees and offices in Germany, France, Poland and the US. It was advised in the transaction by J.P. Morgan, Hogan Lovells und PWC.
Volkswind also owns subsidiaries in the UK, US and Poland. Axpo said because they are not located in its core markets they have not acquired these companies, which will continue to operate as a seperate business.
In early July 2015, German energy company EnBW failed in a similar initiative to expand swiftly in the onshore wind sector. It tried to take over insolvent German wind developer Prokon but Prokon's creditors rejected EnBW's offer, deciding instead to transform Prokon into an energy cooperative.