While discussing the resale of a condominium unit in the Phrom Phong area with another broker, I discovered to my surprise that the broker was in negotiations to sell the unit for the fourth time.

Here's the interesting part: the condominium itself was still one full year from completion. In fact, the building was still a bare shell.

How is this possible? You may think that most buyers want to see what they are buying, but this is not the case.

Basically, there is a huge amount of traffic in the resale of condominium unit prior to a building's completion. It seems that the "buy new" culture in Bangkok is so great that property speculators are having a field day.

Whereas an off-plan sale from the developer might set you back 80,000 baht per square metre, these units are being mopped up by property speculators who, shortly after putting down the initial deposit, will contact a broker and ask him or her to resell the unit, typically adding on 5% to 10% of the initial purchase price. Take a luxury condominium unit with an initial purchase price from the developer of 15 million baht. Shortly after signing the sales and purchase agreement, and putting down the initial 10%, the owner will try to resell the units at, say, 16 million baht. This would make a clear one million baht profit, from an initial investment of just a few million baht.

The maths is simple: a successful speculator could make a 30% to 40% return in a few months. And, because there are no transfers of title deeds, there is no 2% transfer fee or 3.3% stamp duty.

But is it right that an individual can sell an asset and make so much money and not pay taxes?

The second buyer could also be a speculator, and buy the unit for million baht and sell it again shortly after for 17 million. But where does it stop?

Well, each condominium has its own potential. Regardless of the fact that there are hundreds of new condominium blocks being constructed, only a few have the potential for massive gains, because only a few have the key ingredient, namely "location, location, location". Many have the potential of more modest gains.

The key - apart from having a bit of seed money - is to gauge the economic booms and bust, which is of course easier said than done.

We have experienced a growth period, which might continue for a while longer, but perhaps it's best to wait a few months unit the current political turmoil has passed (or however long it takes) before getting back on the bandwagon. However, with construction levels and real estate prices reaching or even exceeding pre-1997 crash levels, time is running out.

I suppose the real question to ask is why developers are not selling the units at higher prices in the first place. Of course, a developer has its own cash flow to consider, and the risk of not selling the units at all may outweigh the potential loss of sales income.

A shrewd developer is one that keeps unit resale in-house. The commissions earned from reselling the unit - especially if this is done four times over - certainly make up for things.

Neil Simmons, formerly of CB Richard Ellis, is co-director of Soho Properties (http://www.soho-properties.com), a leading real estate agent and location specialist for property in Bangkok.