REIT stocks lost nearly one-fifth of their value in one of the worst trading days ever for real estate companies.

It’s unclear what drove the plunge other than renewed concern about the economy and the financial system. The Dow Jones Equity All REIT Index plunged 19% today after posting a 23% gain last week.

'Anytime you see a big move in the market, REITs seem to do that, times two,' said Mike Kirby, an analyst at real-estate research firm Green Street Advisors. 'There’s no logical reason for a 20% correction in pricing in one day.'

Wall Street Journal