CommSec market share falls 05 March 2015 4:38PM John Kavanagh Commonwealth Bank's execution-only broking business, CommSec, suffered a further decline in its market share in the second half of 2014.CommSec has long been the dominant force in the execution-only market but its share has fallen from 51 per cent in early 2013 to 42 per cent at the end of last year, according to the latest Investment Trends Online Broking Report.Its share fell from 44 per cent to 42 per cent in the six months to December.Investment Trends measures share of primary relationships, meaning it measures the number of customers using the organisation as their main broker.ANZ's execution-only broking service, E*Trade, has also lost share, falling from 17 per cent to 15 per cent over the past two years.Westpac Online Investing's share grew from seven per cent to ten per cent over the same period and nabtrade's share rose from five per cent to eight per cent.The other execution-only brokers with significant share are CMC Markets, with a seven per cent share, and Bell Direct (five per cent).Investment Trends said the number of active online investors rose two per cent from 585,000 to 595,000 in the second half of last year. It said low growth in investor numbers was due mainly to modest expectations for sharemarket returns.nabtrade, CMC Markets and Bell Direct received the highest customer ratings for stock picks, trading ideas and value for money.