Brixton, the UK's largest industrial property landlord and owner of 2.5m sq ft in Trafford Park, Greater Manchester, saw net asset value fall 47% in the past year.
The REIT reported a pre-tax loss of £758.8m and a £673.4m reduction in the value of its portfolio from £1.4bn to £787m.
Brixton scrapped its final dividend and said nothing of an expected rights issue.
Borrowing increased from 55% in 2007 to 110% last year and covenants, Brixton said, were "likely to come under pressure".
The group said net rental income rose 6.8% to £77.4m but vacancy increased from 15.4% to 17.3%.
Brixton said its empty rates bill was £3.8m for the year.