• by Joe Mandese  @mp_joemandese, November 2, 2015

In what likely is the biggest deal of its kind since ExactTarget was acquired by Salesforce.com in 2013, another leader in the email marketing services industry has been acquired for a big number: Constant Contact has agreed to be acquired by Endurance International Group Holdings in a cash deal valued at $1.1 billion.

The companies said the value represents a multiple of 12 times Constant Contact’s 2015 estimated adjusted EBITDA, and that it represents a per share premium of 23% over its Oct. 30 closing price of $26.10.

The deal is the biggest of its kind since Salesforce.com paid $2.5 billion for Exact Target in 2013, and the companies indicated that similar synergies were part of the rationale for the deal.

Among other things, the companies cited the following reasons for doing it:

• Expansion of Endurance’s position as a leader in the small business marketing space from Web presence to online marketing services;

• Extension of the company’s product portfolio of solutions and integrated products for its millions of subscribers through the addition of Constant Contact’s suite of online marketing tools such as email marketing, events management, social media integration and contact management systems;

• Strengthening of Endurance’s core capabilities by combining with Constant Contact’s competencies as a trusted and distinct brand focused on product and subscriber engagement; and

• Enhanced operational and financial scale.

Culturally, the deal also brings together two long-time Massachusetts companies. Constant Contact is based in Waltham. Endurance is based in Burlington.