EMERGING MARKETS-Rupiah up, shares down as Bank Indonesia stands pat

* Graphic: World FX rates http://tmsnrt.rs/2egbfVh * Asian stocks https://tmsnrt.rs/3f2vwbA * Bank Indonesia leaves key rate unchanged at 3.75% * Taiwanese shares close at a record high * S. Korean stocks extend gains to a third day By Shriya Ramakrishnan Jan 21 (Reuters) - Indonesia's rupiah edged higher and shares fell after the country's central bank left interest rates unchanged, while South Korean and Taiwanese shares surged on strong export readings from both the tech-reliant economies. Bank Indonesia (BI), which had cut borrowing costs five times last year to support a pandemic-hit economy, left its key policy rate at a record low of 3.75% and said the rupiah was still undervalued and had room to strengthen. A majority of analysts in a Reuters poll had expected the central bank to keep rates steady to maintain an attractive interest rate differential on its high-yielding debt, given the recent rise in U.S. bond yields. "The string of rate reductions in 2020 have yet to bear fruit," said Nicholas Mapa, a senior economist at ING. "We believe BI will remain open to easing policy further in the near-term should inflation remain subdued with IDR stability likely the main decision point." The rupiah was up 0.3% after the decision, while shares in Jakarta traded 0.3% lower. Most other emerging Asian stock markets and currencies strengthened as optimism about the new U.S. administration's hefty spending plans drove buying of riskier assets and dented the dollar's safe-haven appeal. The Malaysian ringgit and South Korean won advanced 0.3% and 0.2% each against the greenback. South Korean shares extended gains to a third straight session, while Taiwanese stocks closed up more than 2% at an all-time high. Data showed South Korea's exports expanded at a much faster pace in the first 20 days of January, and Taiwan's export orders hit a record high in 2020. South Korea and Taiwan have witnessed a strong rebound in exports as the pandemic-driven global shift to remote work spurred demand for memory chips used in laptops and servers. The KOSPI and Taiwan stocks have risen more than 9% each this month. "If global fiscal stimulus and the contact-free digitalisation trend continues post-COVID, Korea's IT, semiconductor and auto exports could outperform market expectations," analysts at Standard Chartered wrote in a note. Indian shares jumped to a record high and the benchmark Sensex scaled the 50,000 level for the first time, boosted by heavyweight Reliance Industries after the country's stock exchanges approved a $3.4 billion deal with the Future Group. HIGHLIGHTS: ** Indonesian 10-year benchmark yields are up 2.3 basis points at 6.298% ** Top gainers on the Singapore STI include Jardine Matheson Holdings Ltd up 2.67% at S$57.71, Jardine Cycle & Carriage Ltd up 2.39% at S$23.09 ** Top losers on the Jakarta stock index include Duta Intidaya Tbk PT down 6.99% at 346 rupiah; Sumber Global Energy Tbk PT down 6.97% at 935 rupiah Asia stock indexes and currencies at 0818 GMT COUNTRY FX RIC FX FX INDEX STOCKS STOCKS DAILY % YTD % DAILY YTD % % Japan +0.00 -0.27 0.82 4.78 China -0.02 +0.99 1.07 4.27 India +0.10 +0.14 0.67 5.45 Indonesi +0.29 +0.43 -0.25 7.27 a Malaysia +0.29 -0.29 -0.39 -1.96 Philippi -0.01 -0.09 -0.04 0.01 nes S.Korea +0.19 -1.09 1.49 10.00 Singapor +0.00 -0.27 0.51 5.99 e Taiwan +0.15 +0.39 2.20 9.65 Thailand +0.10 +0.03 0.00 4.58 (Reporting by Shriya Ramakrishnan in Bengaluru; Editing by Arun Koyyur)