Global mergers and acquisitions of real estate investment trusts (REITS) - expected to be taken up soon by UK property firms - have reached a record value of about $47 billion (£25.2 billion) so far this year, according to research firm Dealogic.

Experts said many REITS have been under-valued by the stock market and have either been sold to private equity buyers or have sought deals with other publicly traded property funds.

Most of the action has been in the United States, with $43.4 billion (£23.3 billion) of the announced deals so far in 2006, by far the highest ever.

"Some people think the stock market is not adequately valuing (REITS), so they put their companies up for sale," said REIT expert Jonathan Mechanic, chairman of the real estate department at US law firm Fried Frank Harris Shriver & Jacobson.

"They end up selling either to private equity or selling to another public company - who under-stand the assets and maybe are valuing better than the public market is. It's going to be a big year. There's more to come."

Sometimes, buyers want the management teams of acquired companies to stay in place and manage their investments.

"A lot of this capital is looking for more than just a pile of properties," said Lou Taylor, senior real estate analyst at Deutsche Bank Securities. "They would like an operating platform. So they are going to buy companies and keep management in place.

"For the selling companies themselves, that is almost nirvana," added Taylor.

"They sell at a premium. They get a big windfall. They keep their jobs - and they get a piece of the future operation."