BRUSSELS, June 3 (Reuters) - Belgian property investment group Befimmo (BEFB.BR: Quote, Profile, Research) announced a 166.6 million euro rights issue on Wednesday to boost its balance sheet after an almost 50 million euro net loss for the six months to the end of March.

The firm will issue 3,731,134 new shares with the support of its main shareholder, Fortis Insurance Belgium, which will exercise all of its preferential rights, subscribing 701,351 new shares for 31,315,322 euros, Befimmo said in a statement.

"The subscription price per new Befimmo share represents a proportion of 24.45 percent of the weighted average price for 3 June 2009 of 62.47 euros, less the gross amount of the interim dividend," the statement said.

Credit Suisse Securities Europe Limited, Dexia Banque Belgium SA, Fortis Bank SA and ING Belgium are acting as joint global coordinators and joint bookrunners for this operation. KBC Securities SA is joint-lead manager.