Information memorandums (IM), which include a more detailed account of the unit's finances, were sent to potential bidders last week, the people said. Bids are usually due about four weeks after information packages have been distributed.

Financial bidders Brookfield, CVC, a tie-up of Blackstone and Carlyle as well as a consortium consisting of Advent, Cinven and the Abu Dhabi Investment Authority have received the IM, they said.

Private equity firm Hellman & Friedman also received the information package, one of the people said. A separate source, however, said the investor was an unlikely bidder for the asset.

Finland's Kone and Japan's Hitachi are the only strategic bidders in the process, the people added.

Sources told Reuters last month that Kone might team up with a private equity partner to mitigate antitrust risks, for example by selling on assets in regions where there is great overlap with Thyssenkrupp, most notably in Europe.

Kone has been talking to CVC about a tie-up but no decision has been made, the people said, adding Kone has hired law firm Clifford Chance to look specifically into how antitrust concerns can be tackled in a possible deal.

The law firm also acted as Kone's advisor in connection with a past European cartel probe against elevator makers, which included U.S.-based Otis, Thyssenkrupp and Switzerland's Schindler.

All parties declined to comment or were not immediately available for comment.

The sale or listing of Thyssenkrupp Elevator Technology (ET), the conglomerate's most profitable unit, lies at the centre of a financial restructuring plan for the stricken submarines-to-steel group.

The elevator division is being marketed based on annual earnings before interest, tax, depreciation and amortisation (EBITDA) of about 1 billion euros (£860 million), one of the people said.

This would give the division an enterprise value of about 15 billion euros if more favourable multiples of stronger rival Kone are applied.

The size of any bids will depend on how much detail Thyssenkrupp provides during the data room phase, which is the first time bidders get a more granular breakdown of the asset.

A lower cash conversion rate -- which measures the degree of how cash flow translates into profit -- compared with rivals will weigh on the division's valuation, one of the people said.

(Reporting by Arno Schuetze, Christoph Steitz and Tom Kaeckenhoff; Editing by Michelle Martin)