The $100 million gap is a result of a mistake made by Goldman Sachs, the financial adviser to Tibco - OCTOBER 2014

According to a filing with the Securities and Exchange Commission, a mix-up with spreadsheets during the final days of negotiations led Goldman Sachs to misrepresent to Vista the number of outstanding shares in Tibco. Vista made its bid based on the number of shares Goldman Sachs said were outstanding in the company, offering $4.3 billion, or about $24 a share, and beating out other bidders. But it turns out Goldman Sachs had double-counted some shares as both common stock and equity awards. That inflated share count was used in Goldman's financial analysis of the deal, and used to calculate the headline number put out in the press release. Instead, Tibco actually has a smaller number of shares outstanding. That means when Vista ultimately closed the deal, it will be paying that same $24-a-share price, but on a smaller number of shares than it originally thought. As a result, Vista will pay about $100 million less than it originally expected.

Nasa metric confusion – September 1999

The conversion of the metric system still confuses those both here and across the pond, and cost NASA $165.6m back in 1999. A team of Lockheed Martin engineers failed to convert units from the English imperial system to metric when building a software system for their new Mars orbiter. The muddled data controlling its thrusters led to the orbiter being lost in space, and NASA were substantially out of pocket.

Spreadsheet errors cost UK taxpayers £40 million in – October 2012

Faulty risk assessments and forecasting errors in an Excel spreadsheet lead to the total breakdown of the government’s tender process for the £9 billion West Coast Main Line franchise. Virgin rival FirstGroup was initially handed the contract but after pressure from Sir Richard Branson to review the decision, PwC alerted the transport minister that “errors had been found in the way the risks were evaluated in each bid”.

The result? A £40 million refund to four of the bidders and the cancellation of FirstGroup’s contract.