With the economy bearing down, Donald Trump's real-estate business has hit new snags that imperil several big projects that bear his name.

The latest troubles - following a bankruptcy filing by the casino company he founded and a dispute with lenders at a Chicago condo project - come in Las Vegas. Three-fourths of the buyers of condo-hotel rooms at the Trump International Hotel & Tower Las Vegas have failed to close contracts, according to public records and people familiar with the project.

Wall Street Journal