The natural location for UK payments firm Zilch Technology Ltd.’s public listing should be its hometown of London. Instead, there’s a real chance the company, last valued at $2 billion, picks the US.That would put it in the growing list of European companies chasing higher valuations in New York, attracted by its deep financial pools. With start-ups often struggling to access proper funding to grow, there’s widespread unhappiness with Europe’s markets, which have failed to keep up with the needs...