Aviva, Britain's second-biggest insurer by market value, said the company's investment unit mistakenly sent an email dismissing its entire staff before retracting the message.
The email, which was sent by the Aviva Investors human resources department to 1300 employees globally, told recipients to turn over company property as they left the building and reminded them of their obligation to guard the firm's confidential information, said Paul Lockstone, spokesman for the unit.
"It was intended that this email should have gone to one single person," Mr Lockstone said.
"Unfortunately, as a result of a clerical error, it was sent to all of the Investors staff worldwide."
Most people recognised immediately that the email was a mistake, he said, adding, "From time to time, things go wrong."
The human resources department issued an apology "fairly quickly" after the message was sent, Mr Lockstone said.
The email is part of the company's administration process when people leave the organisation, he said. News of the mistake was reported earlier today by Britain's Daily Telegraph.
Aviva has been scaling back its asset-management business as the European debt crisis and the deteriorating British economy crimps sales.
The insurer said in January it would cut 160 jobs at the unit. Some of the employees affected by that process have still not departed, Mr Lockstone said.
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