The asset sell-offs aren't collateral for the loan. They're part of the IMF's "good government" requirements. Some of those requirements are perfectly reasonable, reining in corruption and state embezzlement and such. But they make very politically controversial demands to cut subsidies, lay off government workers, and privatize state-owned industries like railroads, airlines, telecoms, power plants, even minerals and oil. And privatizing those industries means selling them off to the highest bidder: typically Western foreign capital.