The nation’s 10 biggest business groups saw their market capitalization on the main bourse drop sharply over the past few weeks or months in the wake of lackluster exports and foreigners’ net-selling streak.

According to Chaebol.com, a conglomerate data tracker, listed units of the 10 conglomerates lost about 40 trillion won ($34.4 billion) in their collective market capitalization this year to date.

It fell by 5.5 percent from 719.6 trillion won on Jan. 2 to 679.6 trillion won as of July 23.

The market cap of Samsung units including Samsung Electronics dropped by 6.2 percent to 327.7 trillion won with their share in the stock market falling from 25.9 percent to 21.7 percent.

Hyundai Motor Group suffered a more serious loss. It sank 18.2 percent, or 22 trillion won, from 120.9 trillion won to 98.8 trillion won. The Hyundai units’ share in the bourse fell to 6.5 percent from 8.9 percent over the period.

POSCO Group posted the heaviest drop with its market cap plunging by 29.4 percent, or 8.8 trillion won, to stay at 21.4 trillion won. Its share stood at 1.4 percent, compared with 2.2 percent on Jan. 2.

Hyundai Heavy Industries and SK Group saw their stock value drop by 8 percent and 0.8 percent, respectively.

Among other major groups that gained in value, to the contrary, were Hanwha, Lotte, GS, LG and Hanjin.

By unit, Samsung Electronics saw a drop of 7.2 percent, Hyundai Motor of 18.3 percent, SK hynix of 18.3 percent, POSCO of 31.2 percent, Hyundai Mobis of 16 percent, Samsung Life Insurance of 12.6 percent, Kia Motors of 19.1 percent and SK telecom of 11.5 percent.

Many research analysts say their bearish situation was attributable to the export slump following the Korean won’s strong position versus the Japanese yen in the first half, which was linked to weak price competitiveness on the global stage.

Some market observers alleged that aggressive short-selling by a group of institutional investors had caused the blue chips’ irregular loss.

By Kim Yon-se (kys@heraldcorp.com)