The East Midlands economy could lose as much as £45m annually when one of its largest firms closes its doors, according to a new study.
Drug firm Astra Zeneca is closing its Loughborough research base at the end of 2011 with the loss of 1,300 jobs.
The East Midlands Development Agency (EMDA) study estimates the firm's expenditures locally are £27m.
The impact will depend on how many workers move away to take jobs and how many remain, an EMDA spokesman said.
Astra Zeneca vice president Rodger McMillan said: "Astra Zeneca is not the only company that is cutting back at the moment… however with the qualifications and the transferable skills that our staff have, we are very optimistic that they can find opportunities if they want to move outside of the industry."
The firm is attempting to sell the site to investors in Asia and North America, but a buyer has not yet been found.
"Clearly there is a significant impact on the local economy and one that we are looking to further mitigate with actions we are taking at the moment," Mike Carr from EMDA said.
About 400 of the 1,300 staff at the site are expected to take retirement or be relocated to other Astra Zeneca sites.
A further 100 staff would like to either start up their own businesses or retrain for a new career.
The report also found that more than 26,500 visitors go to Astra Zeneca and expenditure on hotels in the East Midlands alone by them is estimated at £190,000.
Astra Zeneca also pays more than £3m annually in business rates.