A third of large companies have made bad decisions as a result of poorly designed spreadsheets, according to a study.
Kenny Whitelaw-Jones, managing director at financial modelling firm F1F9, said "poorly constructed spreadsheets" were to blame.
A survey of 1,277 UK senior managers and C-suite executives found one in five large British businesses suffered direct financial loss because of spreadsheet mistakes. Just one in five businesses was confident their spreadsheets contained no errors.
The firm's report Capitalism's Dirty Secret found 59% of respondents admitted their companies "spent nothing" on external spreadsheet-related training in the last year.
In the finance and accounting sector, where spreadsheet analysis was seen as a "core skill", 40% of companies spent nothing on training. In addition, 30% of financial decision makers said they had never received any education.
In terms of financial costs, Whitelaw-Jones said the franchise for the West Coast Main Line had to re-tendered due to a spreadsheet error in a bidding process, which cost taxpayers around £60m.
He added spreadsheet problems caused stress for employees: "We see that from time to time there's one analyst, one individual who built this model and actually the only one person who understands it. What does it mean for that individual? It means long working hours, late nights, incredible pressure, and of course, mistakes get made."
Whitelaw-Jones explained spreadsheets were used for a variety of purposes such as budgeting, forecasting, financial reporting, capital investment decisions, pricing decisions and operation analysis.
"There isn't very much you can point to in terms of business decision making that doesn't involve spreadsheets," he said. "What the data confirms is this is happening in businesses all over in this country and by extension all over the world."
To reduce the risk in spreadsheet modelling, Whitelaw-Jones suggested companies adopt a modelling standardisation, such as the FAST Standard, an open industry standard supported by a number of accountancy and financial firms.
The report also highlighted 20 principles for good spreadsheet practice, a paper published by the Institute of Chartered Accountants in England and Wales last year.