An investor group led by Siris Capital Group has agreed to buy Digital River in a deal valued at about $840 million. Terms of the deal call for Siris to buy all outstanding Digital River shares for $26 each cash. Minneapolis-based Digital River provides Commerce-as-a-Service solutions. Digital River has the right to solicit alternative offers from third parties during a 45-day “go shop.” Macquarie Capital and Sankaty Advisors are providing debt financing. Morgan Stanley & Co. advised Digital River, while Union Square Advisors and Evercore Partners provided financial advice to Siris.