The London Stock Exchange has migrated the 50 largest AIM stocks to its hybrid electronic order book, SETSmm. The move comes as Plus Markets - whose chief executive Simon Brickles is the former head of the Exchange's junior market - launches its own quote-driven trading system for AIM-listed stocks.
The LSE says it has transferred the constituents of the AIM 50 index, together with the 100 remaining small cap stocks, to the SETSmm trading system.
Commenting on the move, Martin Graham, director of market services and head of AIM at LSE, says: "We believe that these measures will deliver increased visibility and reduced trading costs and will stimulate greater retail and institutional investor participation in AIM, benefiting the whole market."
Plus Markets, which also operates the third-tier Ofex market, launches its own alternative trading service today. Five market-makers — Winterflood Securities, Teather & Greenwood, KBC Peel Hunt, Cenkos Securities and Hoodless Brennan — will initially help to operate the market.
Many market-makers have opposed the LSE's extension of SETSmm to AIM stocks and claim the system's tighter spreads lowers incentives for market-makers to deal in smaller company shares.