According to Ford Motor, its Focus model was the best-selling car in the world in the first half of 2013. The claim is based on global vehicle registration data provided by the auto research firm Polk.
The Focus' global sales are up 20 percent his year, totaling 589,709 units. Ford also claimed the Focus the best-seller worldwide in 2012, having sold more than 1 million of the cars that year.
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The title of No. 1 nameplate worldwide is often in dispute because different automakers have different methods for counting vehicles sold under a particular name.
Toyota disputed Ford's assertion last year, countering that the Corolla was tops in the world. Corolla models have different names in different markets.
CNBC has been unable to independently confirm the latest Polk global sales figures.