The Blackstone Group has raised its offer for Equity Office Properties Trust, eclipsing a rival bid by 2.4%, and more than doubled its break fee should the largest buyout to date fail to complete.

Blackstone has raised its offer to $38.3bn (€29.5bn), or $54 per share, topping a rival bid of $52 per share led by Vornado Realty Trust. Blackstone had previously bid $36bn, or $48.50 per share, for Equity Office in November. The deal would be the largest leverage buyout on record.