The Exchange has registered 31 market makers who together will support the 200 stocks traded on SETSmm, with each traded security having at least five registered market makers available.
Commenting on the new service, Martin Wheatley, the Exchange's Deputy Chief Executive, said: "The Exchange is delighted to see SETSmm go live today. The benefits to our customers will include tighter spreads, greater transparency and improved liquidity for the FTSE 250 stocks."
SETSmm is a trading service for FTSE 250 securities currently traded on SEAQ, as well as other qualifying securities. It is an electronic order book based on SETS with the added support of continuous liquidity provision from registered market makers.