Fledgling exchange Plus Markets (PMK:AIM) claims to have surpassed the London Stock Exchange (LSE) in Aim trading volumes for the 80 or so dual-traded securities.

Dual-traded shares are those dealt through both the LSE’s and Plus’ trading platforms. In February, 51% of all trades in the 80 were executed through its systems says Plus.

This looks like good news for investors as dual-trading is said to improve liquidity, driving down spreads and reducing minimum deal sizes.

As an investor you are not able to access the LSE or Plus’ trading platforms. The platforms are the places market makers advertise their bid/offer prices to the brokers who then deal through the market makers on your behalf.

Plus says that market makers competing across the two platforms improves liquidity, a view Aim companies appear to be subscribing to given the steady growth of those opting for dual trading.

The LSE points out that many of the market makers putting prices up on the Plus system are the same ones operating on its system rubbishing the competition idea and branding promises of improved liquidity as an ‘illusion’.

The Financial Services Authority (FSA) is currently reviewing the regulatory regime for UK equity markets like Plus and Aim. At the moment Aim companies have to apply individually to be dual-traded on Plus.

Plus hopes the FSA’s review will mean it will be the investors who are free choose where to trade, as is the case for main market securities, rather than have to wait for their company to make an application.