The European Commission has opened a formal investigation to determine whether changes to Ireland’s flat tax regime for maritime shipping infringe Community State aid rules. In 2002, the Commission approved an Irish tax regime that relieved shipping companies from paying company tax and instead imposed a flat rate tax based on the tonnage of the company’s fleet. To qualify for the flat rate tax, a shipping company’s fleet must have a ratio of at least one owned ship for every three ships with a “time-chartered” crew—a crew chartered for a period of time. In 2007, however, Ireland notified the Commission of its intention to amend the time-charter rules retroactive to 2006, allowing a shipping company to qualify for the flat rate tax with a wholly time-chartered fleet. In prior decisions involving maritime tonnage tax schemes, the Commission has always required a ratio of at least 1:3, or 1:4 in relation to owned and time-chartered ships. Interested parties may submit comments to the Commission.