The owner of Birmingham's Bullring shopping centre has reported a £226.7 million loss for 2018.
Hammerson said the loss comes as a result of a near £80m loss on sales of its properties, and £161m following the revaluation of some of its other properties.
The company, which also owns Bicester Village designer outlet and London's Brent Cross centre, had reported a £413m profit for 2017.
With the number of high-profile retailers going into administration or closing stores, Hammerson boss David Atkins said it had been a "tough year".
"Tenant failures, the structural shift in retail and a more considered consumer created a difficult operating environment, putting pressure on property values," he said.
Net rental income dropped 1.3% at its main UK destinations and 4.3% across its retail parks. The value of its portfolio fell by 5.9% to £9.94 billion, while the values of its UK properties decreased by 11%.
Hammerson said it has held discussions with activist investor Elliott Advisors, which holds a large stake in the company. Following the discussions, Elliott said: "This increased focus on strategic disposals, as marked by updated targets for 2019 and a current pipeline of potential sales of over £900m, signals a positive development in the company's progress, and its ability to ensure that its portfolio of high-quality assets delivers compelling value for all shareholders."