By , LONDON (Reuters) - Europe will see its biggest transfer of share trading in more than two decades when stock exchanges open for business in 2021, with Brexit shifting its centre of gravity away from London.While market players hope that years of preparations since Britain voted to leave the European Union means the transition of most euro-denominated assets like shares and derivatives out of the country will be relatively smooth, the long-term impact is unclear.“This is a big bang event and that is one of the things that the market hasn’t truly understood yet,” Alasdair Haynes, chief...…By , LONDON (Reuters) - Europe will see its biggest transfer of share trading in more than two decades when stock exchanges open for business in 2021, with Brexit shifting its centre of gravity away from London.While market players hope that years of preparations since Britain voted to leave the European Union means the transition of most euro-denominated assets like shares and derivatives out of the country will be relatively smooth, the long-term impact is unclear.“This is a big bang event and that is one of the things that the market hasn’t truly understood yet,” Alasdair Haynes, chief...WW…