Private equity was not always central to the ambitions of the largest law firms – a decade ago many of the biggest viewed it as slightly niche, leaving mid-tier firms to pick up many of the mandates. But last year’s initial public offering boom showed that big international law firms are now the principal advisers to the private equity industry.

European issuers backed by financial sponsors raised more than $35 billion through IPOs in 2014, according to Dealogic, easily beating the previous record of just over $21 billion in 2006. Many of those deals as well as recent buyouts have been more complex and wide-ranging than in the past, which may explain why the dominant legal advisers to European buyouts in 2014 were several of Europe's top five Magic Circle firms or US law firms with a big London presence and an extensive European network.