Financial markets have spent decades becoming faster, cheaper and more accessible. The next frontier appears to be time itself.
The London Stock Exchange plans to launch a separate overnight trading venue in the first half of 2027, initially providing access to exchange-traded products outside the traditional trading day. While the LSE’s main market will continue to operate between 8am and 4.30pm, the new venue is expected to run from 5pm until 7.50am, with a short break for end-of-day processes.
London is not alone. Major US exchanges are also moving towards longer trading hours, while cryptocurrency markets have already accustomed many investors to the idea that markets should be available whenever they want to trade.
For investors operating across different time zones, the attractions are clear. Yet the development raises a more fundamental question: if markets can remain open for longer, does it necessarily follow that they should?
Being open is not the same as being liquid
Extending trading hours increases access, but access and liquidity are not interchangeable.
Traditional exchange hours concentrate large numbers of buyers and sellers into a relatively defined period. That concentration contributes to market depth and price discovery, particularly around opening and closing auctions when institutional activity can be substantial.
Extending the trading day could attract additional participants rather than simply redistributing existing activity. The LSE has identified international retail demand, including from Asia, as one potential source of overnight trading. Investors would also have greater ability to respond to corporate, economic or geopolitical developments rather than waiting for London to reopen.
But there is another possibility. If existing liquidity is spread across more hours, certain periods could have thinner order books, wider spreads or greater price sensitivity to relatively modest trades. For institutions, the relevant question may therefore be not simply whether a venue is open, but whether sufficient counterparties are active to support efficient execution.
The important measure may be not how many hours a market is technically available, but how much meaningful liquidity exists during those hours.
When does extended become continuous?
If investors benefit from trading overnight because information does not respect traditional exchange hours, the same argument could eventually be made for weekends. The progression from conventional trading hours to extended sessions, then towards 24-hour weekday trading, raises an obvious question: is enough ever enough?
Cryptocurrency markets have already demonstrated that round-the-clock trading is technologically feasible, though applying the same model to regulated securities markets raises very different operational and market-structure considerations. Traditional markets do not close simply because exchanges lack the technology to keep them open. Settlement processes, corporate actions, reconciliations and operational controls all have to be accommodated.
There may also be value in concentrating liquidity. A market with fewer trading hours but deeper participation during those periods could, in some circumstances, offer better execution than one that is continuously available but intermittently thin.
Does immediacy always improve investment decisions?
Continuous access also rests on an assumption that the ability to respond immediately to new information is inherently valuable.
Sometimes it clearly is. An investor facing a significant change in risk may prefer the opportunity to adjust an exposure rather than wait several hours for a market to reopen.
For institutional investors, however, speed is only one consideration. Execution quality, market impact, available liquidity and confidence in price formation may be considerably more important than simply being able to transact immediately.
The ability to trade immediately should not necessarily be confused with the need to trade immediately.
This distinction could become increasingly important as technology removes more of the practical constraints that historically determined when markets opened and closed.
Financial markets have continually evolved towards greater accessibility, and extended trading represents another stage in that process. For international investors operating across time zones, the benefits could prove significant.
But every extension creates the possibility of another. If overnight trading succeeds, why stop at weekdays? If weekend trading becomes viable, why stop at 24/5?
The future may ultimately involve markets that rarely, if ever, close. The more important question is whether continuous access would create continuously better markets – or simply more hours in which investors are able to trade.