Typically real estate companies use properties as collateral for loans. So they can't sell those properties unless they pay back the rest of the loan at the sam

Typically real estate companies use properties as collateral for loans. So they can't sell those properties unless they pay back the rest of the loan at the same time, which they probably can't. They might have some properties that are not collateral, but even selling those imposes a problem: in the current market, most likely they will be sold well below book value. This automatically devaluates the value of any other property which they would like to use in the future for collateral and it will make existing lenders very nervous as well.