* KOSPI eases after hitting near 4-week high
* Phone makers slightly up after Apple iPhone 5 unveiling
* Apple suppliers lose ground
SEOUL, Sept 13 (Reuters) - Seoul shares were flat in morning trade on Thursday, as caution prevailed ahead of a possible decision by the U.S. Federal Reserve on further stimulus steps, while the Bank of Korea's unexpected move to hold interest rates steady had little impact.
Some parts suppliers to Apple Inc fell after the U.S. tech giant unveiled its new iPhone with a bigger screen and faster wireless technology, but failed to offer major surprises.
The Korea Composite Stock Price Index (KOSPI) traded up 0.09 percent at 1,951.76 as of 0240 GMT after hitting nearly a 4-week high the previous session.
"Expectations about the Fed meeting have been largely priced into share prices, and investors want to check its results rather than making bets," Lee Jae-hoon, an analyst at Mirae Asset Securities.
A Reuters poll showed economists raised their bets on a third round of Fed bond buying known as quantitative easing (QE)to 65 percent from 60 percent in August.
South Korea's central bank unexpectedly held interest rates steady on Thursday in order to give it time to assess whether a euro-zone bond-buying programme will help allay Europe's financial crisis.
"Investors also see little reasons to dump shares on the options expiry day today," Lee said.
Sustained institutional buying propped up the market, while foreigners turned into net sellers.
Shares in Samsung Electronics rose only 0.4 percent and LG Electronics gained 1 percent.
"Apple's iPhone 5 is not fun. It is not sexy. It is unfortunate for Apple to come up with such a phone, but this does not come as good news to other smartphone makers, either," Lee Sun-tae, an analyst at NH Investment & Securities, said.
He said that with a lack of innovations, smartphones were becoming commoditised, and smartphone makers had to increase subsidies to boost sales, which hurt margins.
Apple suppliers lost ground, with flat-screen maker LG Display down 2.2 percent and chip producer SK Hynix losing 1.4 percent.
Insurers bucked the market, led by Hyundai Marine & Fire which jumped 4.7 percent.