COLOMBO - The Sri Lankan rupee closed higher on Thursday, a day ahead of the central bank's policy rates review, boosted by dollar sales by banks in lacklustre trade, market sources said.

** The stock market fell for the fourth straight session to a near four-month low as foreign investors exited from the island nation's risky assets.

** The rupee ended at 179.45/65, compared with Wednesday's close of 179.50/70.

** Sri Lanka's central bank is expected to leave its key interest rates steady on Friday, a Reuters poll showed, as the island's economy slowly recovers from a political crisis that sparked credit downgrades by all three major global rating agencies.

** The local currency had posted a weekly loss of 0.42 percent in the last week due to high dollar demand from importers and outflows from the stock market.

** It has risen 1.8 percent so far this year as exporters converted dollars and foreign investors purchased government securities amid stabilising investor confidence in Sri Lanka after the country repaid a $1 billion sovereign bond in mid-January.

** The bond market saw inflows of 3.3 billion rupees in the week ended Feb. 13, recording its fourth straight weekly inflow, the latest central bank data showed.

** Worries over heavy debt repayment after a 51-day political crisis that resulted in a series of credit rating downgrades dented investor sentiment as the country is struggling to repay its foreign loans.

** Sri Lanka has raised its borrowing limit for dollar-denominated bonds to $3 billion and chosen seven lead managers to tap the international market as soon as possible, three government sources said on Tuesday.

** The rupee dropped 16 percent in 2018, and was one of the worst-performing currencies in Asia due to heavy foreign outflows.

** The Colombo Stock Exchange index fell 0.7 percent to 5,839.04 on Thursday falling for the fourth straight session, its lowest close since Oct. 26.

** The benchmark index had fallen 0.92 percent last week, after losing 0.3 percent in the previous week. It declined about 1 percent in January.

** The turnover was 1 billion rupees, more than last year's daily average of 834 million rupees.

** Foreign investors were net sellers of 43.1 million rupees worth of shares on Thursday, extending the year to date net foreign outflow to 5.2 billion rupees worth of stocks, and 18.5 billion rupees since the political crisis began on Oct. 26, 2018.

(Reporting by Ranga Sirilal and Shihar Aneez; Editing by Rashmi Aich) ((mailto:ranga.sirilal@thomsonreuters.com; +94-11-232-5540; Reuters Messaging: ranga.sirilal.thomsonreuters.com@reuters.net ; www.twitter.com/rangaba))