SEOUL, April 18 (Reuters) - South Korea's main KOSPI share index was down 0.6 percent at 1,911.52 as of 0042 GMT. The index opened down 0.4 percent at 0001 GMT.
Stocks on the move on Thursday include:
**DONGKUK STEEL UP ON EXXON MOBIL APPROVAL AS VENDOR**
Shares in Dongkuk Steel rose 3.7 percent after the company said Exxon Mobil approved it as a project vendor eligible to supply steel plates for Exxon Mobil's offshore structures.
"We are now able to participate in biddings in order to supply steel plates for Exxon Mobil's future offshore projects, giving us opportunities to expand in this high-value business," a Dongkuk spokesman said on Wednesday.
**KOREA AEROSPACE UP ON BOEING'S HELICOPTER SALE**
Shares in aircraft parts maker Korea Aerospace Industries (KAI) rose 3 percent in early trading after South Korea said on Wednesday it would buy AH-64E Apache Guardian attack helicopters worth 1.8 trillion won ($1.6 billion) from Boeing Co.
"This attack helicopter deal is expected to generate roughly 36 billion won in additional revenue for Korea Aerospace Industries, as it supplies Boeing with parts worth 1 billion won per helicopter," said Lee Sang-woo, an analyst at Hana Daetoo Securities.
(Reporting by Joyce Lee; Editing by Stephen Coates and Jijo Jacob)