Siris Capital Group is spending $840 million for e-commerce services provider Digital River (Nasdaq: DRIV).

The New York private equity firm led an investor group to ink the deal, which is valued at $26 per share in cash. While the sale agreement has been approved by the Digital River board, terms include a 45-day “go-shop” period in which the Minnetonka, Minnesota-based company can solicit alternative proposals.

If no other buyer comes forth, Siris expects the deal to close in the first quarter of 2015. So far, the private equity firm will finance the deal with a combination of equity and debt, for which it has secured financing.

Digital River, founded in 1994, has provided e-commerce services to a number of big-name clients over the years. They include HarperCollins Publishers Inc., computer manufacturer Lenovo Group, toy company Mattel Inc. (Nasdaq: MAT), and music streaming service Spotify, as well as software giants Adobe Systems (Nasdaq: ADBE) and Microsoft (Nasdaq: MSFT).

The company, which became publicly traded in 1998 during the first Internet boom, has also conducted quite a bit of M&A in its own right. In 2002, Digital River acquired Beyond.com Corp. out of bankruptcy and proceeded to pick up assets being sold by Metatec Corp. in 2003. It purchased Web analytics company Fireclick Inc. in 2004, followed by rival e-commerce provider Commerce5 Inc. in 2005. In 2010, Digital River purchased Journey Education Marketing Inc., a Dallas-based wholesaler and retailer of academic software. Terms of each deal remain undisclosed. More recently, it picked up LML Payment Systems Inc. for $107 million in 2012.

Morgan Stanley & Co. (NYSE: MS) has been managing the sale process for Digital River, while Macquarie Capital (ASX: MQG), Union Square Advisors and Evercore Partners are advising Siris.

The deal comes at a time when M&A among private equity firms and e-commerce providers are common. For more coverage, see Pent-Up Demand for E-Commerce Technology Drives M&A.