Both Singapore and Malaysia have low external debt. External debt is the total public and private debt owing to foreign lenders, so don't assume that all the external debt is owed by the government.

For example, Australia has low public debt of 26% of GDP, but it has an extremely high external debt at more than 1.1 trillion US$. The typical Australian spends more than what he earns, so he has to borrow the difference from Australian banks, which source their funds from overseas lenders. Most Western countries are like that - huge external debt and some also have huge public debt as well. Many Asian countries used to be like that, but after the 1997 Asian Financial Crisis, most Asian countries are very carefull not to borrow too much from outside.

Malaysia's public debt is around 50% of GDP. Singapore's public debt is around 100% of GDP. But because both governments have low external debt, it is still ok.

Which GLC did better? Khazanah or Temasek. Read this article: Temasek Portfolio Lost $39.91 Billion