Capital gain is only tax free if it is not from "business like" investments. Zurich tax office has a
clarification letter on this subject. German only.
For ex.
You can not trade with borrowed money.
If you trade shares, you have to hold them for at least a year.
If you buy options and derivatives they have to be in direct relation to the shares you own.
Capital gains should not be more than 50% of your other incomes.
The sum of all transaction should be no more than 5 times your assets.
otherwise they assume that your capital gain is from a business you do.
For all other form of incomes
§ 16 ff of StG applies - which means they are normally taxed. § 23 explicitly list lotteries as taxable income. § 24 list the exemptions.