Alarm systems developer Visonic plans to delist from the Main Market and this has knocked its share price. Visonic does not have 25% of its shares in public hands so it does not satisfy the requirements for a London listing. Shareholders have to vote on the delisting but it is likely to happen on 5 March. The shares will still be traded on the Tel-Aviv Stock Exchange. Sales were 6% ahead to $42.8m in the six months to December 2009, but they were less than 1% higher at $85.5m for the whole of 2009. Cash flow has been strong. However, the loss of a contract will dent sales in 2010. Shares in instrumentation supplier Renishaw continue to move ahead. The share price has increased by more than 10% in the past week. There is no obvious reason for the rise but share trading volumes are higher than they have been since before the company's trading statement in December. Trading had improved enough for Renishaw to reverse a salary reduction made earlier last year. FTSE TechMARK - RisersVislink (VLK) 28.00p +6.67%NCC Group (NCC) 423.00p +6.42%Skyepharma (SKP) 104.00p +5.58%Renishaw (RSW) 601.50p +5.53%GB Group (GBG) 21.25p +3.66%Renovo Group (RNVO) 28.50p +3.64%Morse (MOR) 41.50p +2.47%Consort Medical (CSRT) 389.00p +2.37%Puricore (PURI) 13.75p +1.85%Trafficmaster (TFC) 29.50p +1.72%FTSE TechMARK - FallersVisonic (VSC) 63.50p -11.81%Imagination Technologies (IMG) 268.90p -3.62%Torotrak (TRK) 27.50p -3.51%Corin Group (CRG) 59.00p -3.28%KCOM Group (KCOM) 45.25p -3.21%Ark Therapeutics (AKT) 16.00p -3.03%E2V Technologies (E2V) 57.00p -2.56%Kewill (KWL) 101.00p -2.42%Phytopharm (PYM) 11.00p -2.22%Vernalis (VER) 88.00p -2.22%