CB Richard Ellis Group Inc is buying most of Dutch bank ING's Real Estate Investment Management for about $1 billion to diversify its client base, a deal which would help ING pay down state aid.

CB Richard Ellis Group Inc -- one of the world's largest real estate services companies, whose brokers link buyers and sellers of commercial real estate as well as landlords and tenants -- said the deal will add almost $60 billion to its properties, up from $37.6 billion at end-2010.

ING, which still needs to pay back 5 billion euros in state aid plus costs following its state bailout, said in a separate statement that the deal would give it an after-tax gain of about 500 million euros, including two smaller deals.

The Dutch government nationalized ABN AMRO in October 2008 and provided capital injections for ING , Aegon and SNS Reaal as it paid out nearly 40 billion euros ($54.2 billion) to rescue its domestic financial sector when the credit crisis swept the globe.

Bankassurancer ING said in November it planned two initial public offerings for its insurance activities as part of a mandatory split-up imposed because of its state bailout, with the listing of its insurance operations in the United States and Europe.

Chief executive Jan Hommen said previously that the two IPOs could allow ING to achieve a higher valuation and raise more money for insurance assets with a combined book value of 21 billion euros.

ING shares were down 0.2 percent at 8.99 euros by 1325 GMT, compared with a 0.5 percent rise of the STOXX Europe 600 Insurance index <.SXIP>.

(Editing by Sara Webb)

ABN Amro