City of London law firm Herbert Smith saw profits fall 22% in 2008, plummeting below £1 million ($1.65 million).
Partners will see earnings drop from £1.04 million to between as low as £808,000 ($1.33 million) for financial 2008-09.
The firm made a profit last year.
Herbert Smith in April announced a redundancy consultation at its London HQ, targeting 84 positions; but no one was fired after staff members signed on for voluntary redundancy or alternative working arrangements.
Herbert Smith was founded in the City of London in 1882 by Norman Herbert Smith, and today has 230 partners and 1,200 fee-earners. It is widely considered to be the UK’s leading litigation practice.