User of TOS (TD ameritrade) here, but not using TOS for DCA because I cannot set standing instruction for TOS to buy every month. Need to manually key in order every time. I believe it is a good because it buys directly into the ETF. And you will be almost assured of the market price due to large volume in the market. To deposit into TOS, you can use DBS internet banking. There is a preference rate between TD and DBS, so it is better than the day's board rate. you can check daily with TD Singapore on what is their rates that day before transfer. However there are some who believes to use unit trust to hedge it back to SGD. They say it removes the exchange rates, but personally i think whatever the hedge is also priced into the UT's NAV. If you want to buy solely S&P500, you should check out those DIY platforms (dollardex, ocbc, FSM etc). I am sure dollardex does not have any platform fees; and OCBC only charges 0.88% sales charge on every buy order. Not sure about FSM or other platforms. Finally, there are robos which offers S&P500 as part of their total solution. Use robos if you want to diversify more broadly and have auto rebalance function. Because robos' fees are based on the portfolio value. in the long run, your fees will be higher with robos. Hope this helps.