Network downtime is costing US firms hundreds of millions of dollars in lost productivity, industry analysts warned today.

According to a study from Infonetics Research, firms operating in the financial and manufacturing sectors suffer the biggest financial losses as a result of network outages.

"The finance and manufacturing verticals are bleeding the most," said Jeff Wilson, principal analyst at Infonetics Research, and author of the study.

"The average financial institution experiences 1,180 hours of downtime per year, costing 16 per cent of annual revenue, or $222m. Manufacturers are losing an average of nine per cent of their annual revenue."

In contrast, the study found that healthcare, transportation/logistics and retail firms fared much better. "These verticals have a fairly low percentage of the workforce connected to the network," explained Wilson.

"The transportation/logistics market fared the best of the verticals we studied, losing just two per cent of annual revenue to downtime, but that's still an average of $32m a year. That's a number sure to keep IT managers up at night."

The report identified application problems as a big source of downtime for all verticals, making up between 20 and 39 per cent of the total annual cost of downtime, with logistics companies feeling it the least, and financial, health and retail feeling it the most.

Infonetics Research noted that the more distributed the network, the more companies are affected by service provider downtime. Human error was found to be the cause of at least a fifth of the downtime costs.