Next time you do your Singapore taxes - take a look at line 7 and 9.
7 is Gains or Profits of an Income Nature Not Includ.....
9 is Income not previously reported.
It's 7 that is the problem. The gahmen here can turn around (as they have just done on NFT sales) and recaterogize your income. This is problem for property speculators (the urban myth is that buying or flipping a home more than two times in a year will cause any capital gain to become income) and day traders.....
Even IRAS is a bit vague on this; "The gains may be taxable if you buy and sell property with a profit-seeking motive or deemed to be trading in properties." (Property here being any property - shares, houses, NFTs).
More from IRAS:
Some criteria used to assess if you are trading in properties are as follows:
Frequency of transactions (buying and selling of properties);
Reasons for buying and selling of property;
Financial means to hold the property for long term; and
Holding period.
Do you see the problem? There is no CGT in Singapore but there is reclassification of capital gains as income....