PARIS, July 16 (Reuters) - European stocks extended their losses arround midday on Wednesday, falling for the fourth time in five sessions as fears over banks' balance sheets kept the market under pressure.

By 1014 GMT, the FTSEurofirst 300 index of top European shares was down 1.1 percent at 1,097.97 points, falling after a tentative recovery in early trade. "Systemic risks can't be ignored, with stocks of Freddie Mac and Fannie Mae spiralling down," said Benoit De Broissia, analyst at Richelieu Finance, in Paris.

Earlier this week, a U.S. bailout plan for top mortgage finance companies Fannie Mae (FNM.N: Quote, Profile, Research) and Freddie Mac (FRE.N: Quote, Profile, Research) gave investors temporary relief, before fears about the health of other financial institutions dragged equities markets lower again.

Royal Bank of Scotland (RBS.L: Quote, Profile, Research) sank 8.3 percent to a 10 year low as worries deepened over earnings at its big U.S. unit Citizens, revenues at its enlarged investment bank arm, and the potential that more capital will be needed if it struggles to sell its insurance arm.

Natixis (CNAT.PA: Quote, Profile, Research) tumbled 14 percent on a report in French newspaper Les Echos which said the French bank was mulling a capital increase and could unveil asset writedowns of more than 1 billion euros when it posts its second-quarter results. Natixis declined to comment.

(Reporting by Blaise Robinson)