British retail investors are to be offered the chance to buy a stake in a new 74-storey tower in Chicago, The Times has learnt.

The Mandarin Oriental Tower, part-opulent hotel, part-luxury residential block, will cost $600 million (£302 million) to build.

When complete, it will be the ninth-tallest building in a city famed for its skyscrapers.

BridgePoint, the private equity group, and movewithus, the estate agent, will sell off-plan hotel rooms and apartments in the tower, with the hotel investor receiving an income based on the occupancy of the room.

The cheapest room is on sale for $600,000, with top-of the-range presale units priced at up to $4 million each. Penthouses in the 784ft tower will cost up to $21 million. In all, 252 hotel condominiums and 250 private residences – all of which come with the full benefits of hotel living, such as twice-daily maid services and a luxury spa and gym – are planned.

Similar investment schemes have been launched before, but this is the first to guarantee a minimum resale price of each unit once the building is completed. BridgePoint guarantees a 15.6 per cent return above the open market resale price.

Nor is that the only potential attraction to investors. The block, due to be completed in 2009, is located in the heart of the city, a short walk from the Magnificent Mile, the Chicago River and the financial and business district. It is close to some of the world’s biggest conference centres – a ready source of hotel-room-seeking visitors – and Mandarin Oriental is known worldwide as much for its high occupancy rates, well above 70 per cent, as its luxurious service.

Furthermore, the developer – Palladian Development, whose controlling Kenny family is close to President Bush – is backing the scheme by making unusually confident undertakings.

It must presell at least half the units in the skyscraper for $300 million before it can draw down any of the $400 million of development loans needed to get construction work off the ground.

It will also pick up the tab for ensuring the resale of each unit for early-stage investors who want out at the completion of the block. Should the market go down between investors buying in and first being able to sell on, the developer is obliged to make up the difference to the investors.

Should Palladian go bust before completion, executives at BridgePoint and movewithus said, investors would get all their money back with interest as it would be held in an escrow account, out of reach of any creditors to the constuction company.

“The collar comes from the developer,” Robin King, of movewithus, said. “In the past, developers said: ‘I will sell off-plan and discount.’ Never before have developers taken market risk.” BridgePoint and movewithus insist that even in a “flat market the minimum profit potential is 40 per cent”.

The Mandarin Hotel has already presold $84 million of units.

Fernando Migliassi, senior vice-president at BridgePoint, whose partners have already bought flats in the scheme, said: “This way of forward-selling is a way of compressing time. It creates a buying group, which allows us to comply with the lending structure by getting preconstruction sales. The investors get preferential terms.

“We are investing at BridgePoint at the same time as the investors on the same terms. We are partners. We will get our cut on exit at the same time as investors. We are introducing something new to them.”

How it works

— A condominium hotel operates as a hotel, with rooms owned individually by investors, who can sell the deeds to their investment whenever they choose

— When the unit owner stays at the hotel, they have access to all of the hotel’s amenities. When the owner wants to stay, they ring the hotel and book their own room

— When the owner is not using the room, it can be made available to guests through the hotel

— Each room owner receives a bill, usually monthly, to cover their share of the costs of everything from services, repairs, marketing, insurance and all other costs of running the hotel

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