Solstice trades as Solstice Mobile and specialises in digital strategy and product development. It counts a raft of blue-chip clients among its customer base.

The firm employs 200 staff and made EBITDA of £2.7m on sales of £16.5m last year. It has offices in Chicago, New York and Buenos Aires.

The deal involves an initial £20m in cash and 2.6m St Ives shares, with a further £25.3m consideration payable dependant upon Solstice’s performance through to the end of 2017.

St Ives chief executive Matt Armitage said the buy would help drive the group’s international expansion plans. “We already have a joint venture in Chicago, and have taken Incite to New York. We’ve taken the view that the time is right to acquire a business in the US. Solstice extends our footprint internationally, and extends our breadth of digital services.

“I think there’s a meeting of minds from a cultural perspective and lots of opportunities from a strategic point-of-view,” he added. “This deal is similar in size to Hive and Realise, and that’s our target. We are very pleased to get it over the line.”

Solstice's existing management team, including founder and chief executive J Schwan, will remain with the business.

In the past the then-print group had acquired print businesses in the Netherlands, Germany and the US but eventually retrenched back to the UK, selling its last overseas print subsidiary in 2009.