Companies could save as much as 2.3 billion euros ($3 billion) in administrative costs thanks to an overhaul of the European Union’s data-protection rules. The proposed changes to the EU’s 17-year-old data protection rules will allow companies to do business in Europe based on just one law. Companies will save a further 130 million euros every year by not having to notify authorities each and every time data is processed.Under the European Commission’s January proposal, companies face fines as high as 2% of yearly global sales for mishandling or losing personal data. The plans would also reduce the number of regulators a company needs to contact for data-protection issues across the region as the regulator of its home base will become a one-stop shop. In practice, this will mean that Ireland’s agency will be in charge of regulating companies like Google Inc. (GOOG) and Facebook Inc. (FB), which run their European operations from the country.Ireland will take over the rotating EU presidency for six months in January 2013.