JP Morgan and Zaoui & Co have emerged as the sole advisers on either side of Nokia’s bid for French rival Alcatel-Lucent – a further sign that while M&A deals have been getting bigger, the number of banks working on them is shrinking.

Finnish company Nokia and France's Alcatel-Lucent, a smaller telecoms equipment maker, confirmed on Tuesday that they were in advanced talks over a deal that would be a "full combination, which would take the form of a public exchange offer by Nokia for Alcatel-Lucent".