Kansas-based Bats announced plans in March to form a European division and recruit an executive team from the local talent pool in London.

In the first round of appointments Hemsley has been appointed chief executive officer of the London-based unit, while O'Donnell has been appointed chief operating officer. The two have been recruited by Bats SVP in charge of business development, Ken Conklin, who has been leading the European plans.

Hemsley was managing director and chief information officer, market solutions, at Euronext Liffe between 2001 and 2004. He left the exchange to take over as CEO of Choreology, a London-based enterprise application integration technology vendor.

Prior to joining Liffe Hemsley was a managing director of global technology - serving as chief operating officer and a CIO - at Deutsche Bank. He has also worked for Credit Suisse First Boston and Natwest Capital Markets and founded corporate advisory business Belvedere Hill.

O'Donnell joined Morgan Stanley in 1994 and was most recently an executive director at the bank's institutional equities division where he was responsible for architecture, planning, deployment and operations of algorithmic trading and smart order routing across a range of asset classes.

Commenting on the appointments, Joe Ratterman, CEO, Bats, says: "We are a technology company at our core, and both Mark and Paul fit the Bats executive profile of high calibre, energetic leaders with a hands-on technology background."

The Bats ECN launched in the US in January 2006 and now claims a 8-10% market share in US equities. An aggressive one month pricing plan introduced in January 2007 helped drive trade volumes and forced both Nasdaq and Nyse to adjust their fees.

On 23 January 2008 the Bats ECN crossed the one billion volume mark for the first time, finishing the day with more than 1.18 billion shares. Bats said it on the day it touched roughly 11.3% of all Nasdaq-listed volume, 10.4% of Amex-listed volume and 8.0% of Nyse-listed shares.

Bats is now looking to replicate this success in Europe by launching its ECN - which is designed to handle high-speed, high-volume and anonymous algorithmic trading for broker-dealers - in the region to take advantage of the EU's Markets in Financial Instruments Directive (MiFID) and compete with the region's exchanges.

Earlier this month the ECN selected IT vendor Savvis to host its European platform at its data centre in London's Docklands. Savvis says Bats' customers will be able to co-locate their platforms in the data centre and use Savvis' proximity hosting service to cut transaction times.