The 2011 Hyundai Sonata is helping drive sales.

While looking over May new-car sales data and compiling this month’s best car deals, I noticed what a lot of other journalists have pointed out. Together, Hyundai and its Kia brand sold 107,426 cars in May. That’s more than Honda, Nissan (including their luxury Acura and Infiniti brands) and Mazda. It’s also just 961 fewer cars than Toyota (including Scion and Lexus) sold. While the Japanese brands had supply issues to deal with, they’re also dealing with older model lines. Hyundai and Kia have almost completely revamped their lineups for 2011, and the competition is looking dated by comparison. Hyundai and Kia have also been growing their sales slowly, before the disaster in Japan crimped the supply chains of Japanese car makers. So far this year, Hyundai and Kia have sold 120,908 more cars than they did in the first five months of 2010. While the issues Japanese car makers face are helping open things up for Korean automakers, they were clearly making a play for increased market share well before the natural disasters.

But here’s the really interesting thing: In the past few months, Hyundai and Kia haven’t offered very good incentives. In June, they are. In much of the country, you can get most Hyundai models with 1.9 percent financing for 36 months, and there are attractive lease deals on the Hyundai Sonata, Accent and Elantra. The same is true for most Kia models. Usually, when a car maker gains market share and sales are good, incentives decline. Hyundai and Kia are bucking that trend. With combined sales just 961 units behind Toyota in May, it’s possible Hyundai and Kia could pass Toyota in June. The two companies were also just 7,937 units behind Chrysler in sales. Though that’s a big gap, with good incentives, it’s not inconceivable that Hyundai and Kia’s combined sales could jump into the top three or four in June.