A new survey shows that four of every five companies lose revenue when their network goes down, and worse yet — one in five has fired an IT employee as a result.

The Avaya study found that companies lose an average of $140,000 (U.S.) as a result of network outages. The business-communications solutions provider surveyed mid-to-large companies in North America and the U.K., finding that 82 percent have experienced some type of network downtime caused by IT personnel making errors when configuring changes to the network’s core. In fact, the survey found that one-fifth of all network downtime in 2013 was caused by core errors.

The numbers are worst in the financial sector, where companies lost an average of $540,000 per incident. And while one in five companies said they gave an IT worker the ax over such an incident, one in three in the natural resources, utilities and telecoms sectors said they canned someone due to network downtime.

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