First of all, you will probably need a brokerage account. When you open a stock trading account with a brokerage firm like UOB Kay Hian, they will give you the option on which markets (e.g. Singapore, Hong Kong, U.S) you want to trade in. There are a few particular forms that you will need to fill in. To trade the US market, you will need a W8-BEN form which is downloadable from their website (usually).
I leave you with a few links that might be useful if you are interested in opening a trading account. As it is really self-explanatory, I will leave it up to the reader to navigate the technical details of how to open a stock trading account to buy US stocks that are listed on the US stock markets.
- UOB Kay Hian. http://www.utrade.com.sg/index.jsp (go to the top menu bar on Getting Started and read the questions. Pretty self explanatory)
- POEMs. http://www.poems.com.sg/ (go to Getting Started on left column)
- Standard Chartered. http://www.standardchartered.com.sg/personal-banking/services/online-trading/en/index.html
- OCBC. http://www.iocbc.com/