Private equity firm Blackstone Group's initial public offering was about seven times subscribed, boosted by demand from Asia, the Middle East and Europe, the Financial Times reported on Thursday.

Citing unnamed people close to the offering, the newspaper said U.S. mutual fund interest was limited by concern over a possible increase in Blackstone's tax liability.

The flotation on the New York Stock Exchange, worth up to $4.75 billion and underwritten by Morgan Stanley and Citigroup, is set to be priced later on Thursday. Blackstone earlier said it expects to sell 133.3 million common units at $29 to $31 each.

The banks will be permitted to sell an additional 20 million shares to meet excess demand.