Shares in French power utility EDF fell sharply on Monday after company lowered its 2018 profit forecasts.
The company, which is also a major electricity services provider in the UK, said it was cutting its earnings targets due to falling energy consumption and falling availability of French nuclear reactors at the start of next year.
French nuclear power capacity is due to fall in the coming months and years as delays to the restart of several reactors after recent upgrades affect output.
Analysts at Jefferies, the brokerage, had recently suggested capacity at French nuclear plants could decline from 63 gigawatts (GW) in 2017 to 14GW by 2030.
As a result, EDF said it now expected core earnings for 2018 to be in a range between €14.6bn and €15.3bn, as opposed to its earlier forecast of at least €15.2bn.
Although the revisions would still represent a "significant rebound" compared to 2017, investors responded with disappointment, sending the shares 8.56% lower to €10.73.