Nasdaq, the US stock market operator trying to buy the London Stock Exchange, has increased its domestic equity market share for the first time in six months amid growing competition from rivals trying to erode its dominant position.

The exchange increased its share of trading in Nasdaq-listed securities to 46.6% in December last year compared to 44.8% in November. Its December market share in New York Stock Exchange-listed stocks also increased, to 14.2% from 14% in the previous month.