Rivals of Bats Europe have warned the London-based alternative trading system that a temporary price promotion that helped establish the firm in the US is unlikely to prove as effective in Europe, despite it boosting the firm's share of UK stock trades last week.

Bats increased its share of UK equity trades to 5.2% so far this month from 3.9% last month, according to Thomson Reuters, after launching a one-month promotion that pays traders more for posting orders than it recoups in fees from customers buying stocks.