A Day at the Exchange: How Securities Trading Works

Until the 1990s, trading in Switzerland and most stock exchanges took place very differently from how it’s done today. There was no continuous trading day -- instead, each stock was called individually. Traders stood in the ring or on the floor shouting out their buy and sell wishes in the room and someone in the middle of the ring tried to find a price at which as many deals as possible would be made. As soon as this was the case, investors could trade a particular share through their bank. They were then “closed” again – until the next call.

This process underwent a fundamental change with the advent of digitalization one year before the turn of the millennium. Today, all trade orders are executed via electronic systems. As a result, there came into being what we today know as the continuous trading day: From morning until evening, orders can be placed, changed, and executed in fractions of a second.

A trading day on the Swiss Stock Exchange follows a clearly defined rhythm. It is divided into different periods, each with their own function. For private investors, it’s helpful to know these phases in order to better understand the dynamics of the market.

After trading ends, the post-trade phase begins. This is where the transactions get settled.

The actual transfer of ownership of the shares and the payment don’t happen right away, rather after a delay of two days, the T+2, as it is known (Transaction Day plus two days). This means that two days after the day of the trade the buyer receives the shares and the seller receives the money for them.  In the future, this process might be reduced to just one day.

But not every trading day’s the same. There are moments where the regular process gets interrupted. Investors should know about these situations.

Sometimes, trading of a specific stock is briefly suspended. This generally happens due to high volatility, for example following important corporate or economic news. In such cases, the exchange automatically halts trading for a brief time in order for the market to stabilize. In particular, such interruptions give professional investors time to review their orders. For example, they’ll look to see if they’ve accidentally entered a large order by mistake. The aim is to ensure trading that is both orderly and fair.

The duration of a trading suspension depends on the stock involved: With blue chips, for example, the wait is five minutes; in the case of smaller companies, it’s 15 minutes. Following such a suspension, the new share price is determined in an auction whereby all open buy and sell orders are factored in. It can be that the share re-opens at a significantly higher or lower price.

Trading suspensions also occur when important corporate news is expected that could cause a big price surge. Such a stop in trading is intended to ensure that all market participants are informed at the same time, and that conditions are fair for all.

• Triple Witching Day: On four Fridays per year, many futures and options contracts expire at the same time. This often results in sharp price movements.
• Holidays and shortened trading days: In the days around Christmas and national holidays, trading can end early. Investors should keep an eye on these dates in order to avoid any stock market surprises.
• Swiss Stock Exchange Closures 2026