COLOMBO - Sri Lankan shares ended weaker on Thursday, falling for a fourth straight session to their two-week low, as investors booked profits ahead of the presidential vote on Nov. 16.

** The country's main Tamil party on Thursday announced their support for Sajith Premadasa, the housing minister and one of the two presidential front-runners, giving him an edge over his rival Gotabaya Rajapaksa

** There are growing concerns over giveaways promised by the two top presidential candidates after officials and a credit rating agency warned that their pledges could push the country deeper into debt.

** The International Monetary Fund approved the release of sixth tranche of a $1.5 billion loan programme for Sri Lanka, but asked the authorities to show fiscal discipline.

** Sajith Premadasa has promised free housing for all, free school uniforms and meals for students, and free fertilizer for farmers among other things.

** Gotabaya Rajapaksa has vowed to cut a 15% value added tax by nearly a half and abolish some taxes as a way to reignite consumption.

** The benchmark stock index ended 0.41% weaker at 5,932.07. Last week, the index rose 1.6% in its fourth straight weekly gain, but is down 1.99% this year.

** Political analysts say the leading candidates are locked in a tough fight, although Sajith Premadasa has been gaining at grass-root level due to his poverty elimination policies and support from minorities.

** Diversified and banking stocks were among the top losers, with Hemas Holdings Plc falling 3.6%, Vallibel One Plc 4.6%, Hatton National Bank Plc 1.1%, conglomerate John Keells Holdings Plc 0.39%, Sampath Bank Plc 1.6%.

** The rupee ended 0.11% weaker at 180.70/181.00 per dollar, compared with Wednesday's close of 180.50/80. The currency is up 1.1% so far this year.

** Foreign investors were net sellers of riskier assets for 11 out of 12 sessions on Thursday.

** They sold a net 13.3 million Sri Lankan rupees ($73,602.66) worth of shares on Thursday, extending the net foreign outflow so far this year to 5.78 billion rupees worth of equities, according to index data.

** Equity market turnover was 599.7 million rupees, less than this year's daily average of about 680.5 million rupees. Last year's daily average was 834 million rupees.

** Meanwhile, foreign investors bought government securities on a net basis for a second time in four weeks, buying a net 1.55 billion rupees worth of government securities in the week ended Oct. 30.

** Total foreign outflows from government securities through Oct. 30 stood at 52.08 billion rupees, central bank data said.

** The central bank left its key rates unchanged on Oct. 11 after loosening policy this year, although growth is likely to remain subdued as the economy faces rising global risks.

($1 = 180.7000 Sri Lankan rupees)

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