In the second quarter of 2013, the Swedish energy utility invested SEK 1.24 billion (EUR 134.8 mllion) in wind power. This was reduced to SEK 735 million (EUR 79.9 million) in 2014's second quarter.
The results were released as part of the government-owned company's first-half-year results for 2014.
Overall in the first six months of 2014, investment in wind fell 10.4% year-on-year to SEK 1.914 billion (EUR 208 million).
A spokesperson for the company said it was difficult to compare the investment results between year-on-year quarters. "It depends on how we book [report] the projects in this case," the spokesperson said.
"All investment has been affected, our overall capex has been cut," he added.
In May, Vattenfall announced it would cut investment to its research and development budget, particularly for offshore wind, as part of a move to reduce its planned five-year wind investment by 46%.
The 2014 half-year results also showed wind production fell 12.5% in Q2 compared with a year earlier. The company's wind projects produced 0.7 TWh in the quarter, down from 0.8TWh in 2013.
The Vattenfall spokesperson said there was "no specific reason" for the year-on-year drop in production.
However, for the first six months of 2014 wind production was up 16% with 2.1TWh produced, up from 1.8TWh last year.
The results announcement is Øystein Løset's last as Vattenfall CEO. He steps down on 1 October and will be replaced by Magnus Hall.
Vattenfall is jointly developing the recently UK government-approved 1.2GW East Anglia One offshore project in the North Sea. Vattenfall is partnering Iberdrola's UK subsidiary Scottish Power Renewable on the project with commissioning planned for 2019.