Seoul shares end at new 15-mth closing high

* Seoul shares end up 1.38 pct

* Samsung Elec hits historical high on sectoral outlook

* Auto issues up on Sept sales expectations

(Updates to close)

By Jungyoun Park

SEOUL, Sept 22 (Reuters) - Seoul shares posted a fresh 15-month closing high on Tuesday after Samsung Electronics (005930.KS) hit a new record peak on a strengthening sectoral outlook and auto issues rallied on sales expectations.

The Korea Composite Stock Price Index .KS11 (KOSPI) finished up 1.38 percent at 1,718.88 points, its highest close since late June, 2008.

"Continued foreign buying lifted shares to their new (2009 high)," said Kim Seung-han, a market analyst at HI Investment Securities, adding that an improving global economic outlook, the FTSE upgrade of South Korea to developed market status, and a stronger won KRW= were keeping foreign appetite strong.

Samsung Electronics led gains as the world's No.1 memory chip maker hit a new historical high on the back of an increasingly rosy sectoral outlook.

"DRAM spot prices continue to trend upward on the back of increased procurement from memory-module makers and the anticipation by DRAM companies of further hikes in contract prices," Daiwa said in a report dated September 21.

Samsung Electronics ended up 3.38 percent to 825,000 won after hitting an all-time-high of 829,000 won, helped further after Citi raised its target price on the company by more than 14 percent to 1,030,000 won ($853.4), citing enhanced earnings momentum.

Citi also raised its 2009 and 2010 operating profit estimates on the world's No.1 memory chip maker by 2.6 percent and 15.2 percent, respectively.

Shares in Hynix (000660.KS) gained 2.8 percent.

LG Chem Ltd (051910.KS) and Samsung SDI Co (006400.KS) rallied after Morgan Stanley raised its ratings on the electric vehicle battery makers to overweight from equal weight, citing potential growth in the global battery market.

"As there are a limited number of proven lithium ion battery makers, LG Chem and Samsung SDI are likely to sign additional contracts with global automakers in the near term," Morgan Stanley said in a report on Tuesday.

It also raised its price targets on both firms' shares, hiking LG Chem to 310,000 won ($256.8) from 140,000 won and Samsung SDI to 210,000 won from 99,000 won.

LG Chem shares jumped 10.81 percent at 246,000 won, while Samsung SDI ended up 6.4 percent at 174,500 won.

Auto and auto parts issues rallied on the back of expectations for positive September sales.

Nomura said in a note on Tuesday it expected South Korean automakers to post month-on-month rebound in September sales for both domestic and export markets.

Hyundai Motor (005380.KS) ended up 5.16 percent and Kia Motors (000270.KS) rose 4.42 percent.

Hyundai Mobis (012330.KS) climbed 7.81 percent helped by a spike in LG Chem stocks and on expectations for the two firms' auto battery joint venture, which was announced in late August.

"Hyundai Mobis shares have tended to move in line with LG Chem stocks lately on the auto battery hopes," said Cho Soo-hong, an analyst at Hyundai Securities.