Blackstone Group plans to book profits from private equity at the time an asset is bought, as the buy-out firm exploits a new accounting standard to smooth out its lumpy income stream.

Blackstone, preparing for a potential $40bn float, wants to treat private equity performance fees as derivatives it can value in advance, a move that would have boosted last year’s net income by $595m (€446m), or 22 per cent, it said in its preliminary prospectus.