Institutional investors should look beyond mid-market corporate direct lending to other parts of the private debt universe, such as US residential mortgages or the UK commercial real estate debt market, according to Willis Towers Watson. Private debt was now a core asset class for institutional investors, but concentrating on mid-market corporate direct lending was “much too constraining” an approach, the consultancy said in a report published last week. Assets under management in private debt grew to a record $667bn (€557bn) at the end of 2017, up 13% on the year before, according to data provider Preqin. This meant the industry had more than tripled in size in the past decade, growing from $204bn as of the end of 2007.