If u buy sell buy sell, and keep repeating it. Yes it is consider as your business income. U need to declare.

If u buy one time, then sell multiple time, that one is investment gain.

A bit hard to explain in details, but definitely trading is taxable (if got profit).

But i do know LHDN did won 1 case against bond trader, won the case by stating badges of trade, macam slap him/her few millions penalty IINM.
Exact number i don't know, it is up to LHDN and court to judge on the amount of transaction.

Posting in sour grape thread

Dah takde keje lain ke. Asalkan dia bukan scammer ke, scalper ke, menyusahkan orang ke, penjenayah ke, ahli politik ke atau /K public enemy numbah one machiem MENJ ka ... Apa dosa dia sampai kacau privacy dia ...