Billionaire Alex Gerko’s quantitative-trading firm XTX Markets is investing more than €1 billion ($1 billion) building five data centers in Finland to underpin its growing use of machine learning. The London-based market maker, which uses complex algorithms to trade over $250 billion worth of assets a day, will build the complex in the area around Kajaani, in central Finland, where it owns a 478-acre site, XTX said in a statement on Wednesday....