Thoma Bravo, a software investment firm, has entered into a definitive agreement to be acquired by Stamps.com, a provider of e-commerce shipping solutions, in an all-cash transaction that values Stamps.com at approximately $6.6 billion.

“As the first company to introduce online postage and an early innovator in e-commerce shipping software, Stamps.com has established itself as a key technology solution in worldwide e-commerce,” said Holden Spaht, a managing partner at Thoma Bravo. “With a highly-seasoned management team that has driven impressive growth for more than twenty years, an innovative suite of market-leading software solutions, and a large and growing customer base, Stamps.com is well positioned to capitalize on the strong secular tailwinds in e-commerce and we are excited to support the Company in its next chapter of growth.”

“Today’s announcement marks a significant milestone in the history of Stamps.com and will provide us with a new and exciting platform from which we can continue to execute our global strategy driven by best-in-class software and technology solutions,” said Ken McBride, Stamps.com’s Chairman and CEO. “With the financial and operational support of Thoma Bravo, Stamps.com can continue to innovate and pursue growth opportunities to capture the expanding e-commerce shipping market and extend our position as the leading global multi-carrier e-commerce shipping software company.”

“We’ve been tracking the impressive growth of Stamps.com for many years and are excited to partner with the Stamps.com team to support the company in continuing to drive cutting edge product innovation, expansion into new markets, and delivery of an even greater level of service and support to its impressive customer base,” said Brian Jaffee, a Principal at Thoma Bravo. “The e-commerce landscape is rapidly evolving and we look forward to partnering with the Stamps.com team to continue building on the Company’s leading position in e-commerce shipping solutions.”

J.P. Morgan Securities LLC is acting as exclusive financial advisor to Stamps.com and Proskauer Rose LLP is acting as its legal counsel. Debt financing for the transaction is being provided by Blackstone Credit, credit funds managed by Ares Management Corp., PSP Investments Credit II USA LLC and Thoma Bravo Credit. Kirkland & Ellis LLP is serving as legal advisor for Thoma Bravo.