Read the article you had attached,Nothing is perfect; a AAA rating doesn't mean 0% risk. It just means it's the safest class of debt investment.
And Singapore's financial position remains stronger than many other AAA countries as quoted in my post above.
"Fitch expects the central government deficit to widen to 15.7% of GDP from 0.3% of GDP in 2019, in line with the authorities' forecast of a deficit of SGD74.3 billion."
So even when savings are being used to finance the deficit, its a negative flow.
Also- "Singapore does not disclose the overall size of its official external assets, notably those of GIC Private Limited, a sovereign wealth fund; GIC states publicly that it manages over USD100 billion of assets, but Fitch believes the size of its external assets is much larger."
So Fitch has no idea about Singapore's sovereign fund and "believes" its more than 100 b usd !!
No wonder the ratings agencies have such low reliability and many companies don't allow them any access.