SEOUL, Oct. 31 (Yonhap) -- Samsung Electronics Co. and LG Electronics Inc. clinched a combined 50 percent share of the U.S. TV market in the July-September period, an industry report showed Monday, thanks to strong demand for their premium TVs with 3D features and Web connectivity. 

It marked the first time the combined sales of Samsung and LG, the world's two largest TV makers, accounted for half of the U.S. TV market on a quarterly basis, according to data released by NPD Group Inc, a market research firm.

Samsung accounted for 37 percent of the third-quarter flat-screen TV sales in the U.S., according to NPD data, followed by LG, which contributed 13 percent of the U.S. TV sales in the period.

Samsung and LG advanced in the third quarter as Japanese TV suppliers lost ground, giving up their market shares to Korean rivals.

Panasonic Corp. and Sony Corp. were the third-largest TV suppliers in the U.S. during the quarter with a 9 percent market share each. Toshiba Corp. was the No. 4 player with 7 percent. 

In terms of unit shipments, Samsung and LG accounted for a combined 36 percent of the flat-screen TVs sold in the U.S. market, according to NPD.

Korean TV makers also posted fast growth in the U.S. 3D TV market. Samsung and LG accounted for a combined 71 percent of 3D TV sales in the U.S. during the third quarter, compared with 57 percent in the first quarter and 69 percent in the second quarter, according to NPD data.

In the meantime, Sony's 3D TV share fell to 12 percent in the July-September quarter, compared with 28 percent in the first quarter. Panasonic held steady at a 12 percent share from the first to the third quarter.

Both Samsung and LG, which engaged in public battles over 3D TV technologies earlier this year, said that they plan to expand sales in the North American market during the second half of this year as they begin to ship new models after summer.