The key to investing in the hangseng (or any market) is to NOT trade daily. Buy and hold, after very thorough investigation.

Nothing. You bought stock. You own the shares until you sell them. The stock price can fluctuate up or down–no way to tell in which direction–if you own it for more than a day.

If you trade on margin you borrow some of the funds that you use to purchase an investment. If the stock drops below a certain threshold, your broker may decide that you don't have enough equity to hold the investment and may force you to sell the stock. But that hopefully won't happen.

My experience has been that a "trade" is considered to be the order ans all of its fills. In the attached link, the SEC makes it very clear that a pattern day-trader is supposed to be a real day-trader. Counting each fill would snare too many customers in the net.

From Rule 2520:
"The term "day[-]trading" means the purchasing and selling or the selling and purchasing of the same security on the same day in a margin account"

"The term "pattern day trader" means any customer who executes four or more day trades within five business days. However, if the number of day trades is 6% or less of total trades for the five business day period, the customer will not be considered a pattern day trader"

It's pretty clear to me that to "execute" a trade. I place an order and get fills. The order and the fills are a "trade". Now, if your two "buys" are based upon two separate orders, then the pattern you ask about would be two day trades.

Further info:
Interactiveborkers gives clear examples of day trades on their website. Another reason why I like that firm so much. Looks like your two buys and one sell example is just one day trade.

If you have a margin account, when you buy a stock your cash is used first. You only use margin (or borrowing money) when you buy more stock than your money will pay for.

If you do buy on margin (or borrowed money) there are only two ways to change it. Deposit more cash to cover the purchase. Or sell securities which will increase your cash position.

The above is for the US.

You better know what you're doing and have been doing for a while. and thay you understand the maket and the rules governing it.

Here are four rules you must have, if you don't you will loose money
1 – A written sound trading/investment plan with rules that will not only help you but more importantly protect you, mostly from yourself.
2 – Sufficient trading/investment capital. Use your own money, there’s no need to go into debt so that you trade/invest.
3 – A written money management program in place. Remember never invest 100% of your capital into any one security and never have 100% of your capital invested.
4 – A full and complete understanding of the rules & regulations of the industry.

Here are some of the rules that I follow, in additiona to the four cardinal rules above.
Never buy or sell based on anyone's, including your own, market predictions.
Stick with up-trending stocks.
Never buy stocks in danger of filing for or actually in bankruptcy.
Never average down.
Always sell when management cuts sales or earnings forecasts.
Only buy stocks with real sales and real earnings.
Always diversify between industries.
Don't buy stocks just because they've gone up.
Never sell a stock because an analyst proclaims it is overvalued.
Always look for companies with new ideas, new styles or new products.
Orders after an execution – a “stop loss”
No security is to be purchased at a price that is below the 50-day moving average price.

Good luck, based on your question, you're going to need it

Yes as long as you have a margin account…. but the "I don't know much about retail accounts" tells me you don't need to be on the short side of the market. There are other requirements to short and it varies broker to broker.

Yes you day trade BUT you can not buy/sell the same security four or more times in five business days.

And it is a Fed rule that when you buy a security it must be paid in full prior to its sale, if you sell with out making payment in full your account is restricted for 90 days or until payment is received and you can not use the proceeds of the sale to cover the purchase amount due.

The $25,000 item that every one talks about is that if you day trade the same stock 4 times in 5 five days you will be considered a pattern trader AND you must
1-open a margin account
2-maintain equity of $25,000 at all times, The 25,000 is NOT a balance but equity and you must have that much in your account at all times.

Actually, day traders MAY qualify to do that, but you have to be a certified investor, which means experience and plenty of cash to cover trades. What that essentially means is you have enough extra cash that the surplus cash is buying and when the trades clear that then becomes the surplus cash. Think of it as a different kind of "margin" that the government requires you keep to do this.

If you're daytrading, then it can be riskier depending on the level of margin you're utilising and the volatility of the stock you're trading… personally I DayTrade and I have no issue with it, equally, if you're doing it sucessfully as well, don't worry and focus on what you see.

Tax-wise… that depends on what country you're trading from and you should obviously discuss the matter with your local authority.

Yes I have. When I first started trading I had an E*Trade account. One month I went to take out some money and I requested a check. I checked to MAKE SURE that they had the right address and they did, so I waited….and waited…and waited. Three weeks later I was told that it was not their fault, even though I never received the check. "We mailed it out," was the only response. I never had any mail not get there from other sources-they dropped the ball somewhere. I ended up having to pay them to cancel the check AND pay for the wire through to my bank-they refused to take ownership of the problem. I told them to forget it and just close the account.

Did you trade during that time? Day trade restrictions are sticky, but usually the rep can remove them on a one-time basis. If its the first time there should be no problem at all. Did you speak to a manager? Thats a day trade call-similar to a margin call but generally much lesser priority. Once you bring the account back up, at most brokers, everything should be roses.

If you are generating that kind of commission any of the other discount houses would be glad to have you. There is no sense in going with such a no frills broker if you are treated like that.