Financial terms of the deal weren't disclosed.
Solid specializes in developing databases that are stored in a computer's high-speed random access memory (RAM), bypassing the hard drive. The result is a system that can deliver data to applications virtually in real time, according to Solid.
Solid's in-memory databases work with applications built for the open, MySQL environment and with commercial applications.
The company was founded in 1992 in Finland and is headquartered in Helsinki. It also maintains operations in Cupertino, Calif. Solid is backed by private equity firms Apax Partners and CapMan.
IBM said it plans to add Solid's operations to its Information Management Software division. It will pitch the company's offerings to customers in industries that need high-speed data systems, such as the telecommunications sector.
"Customer demand for high speed, low-latency, reliable access to business information is growing exponentially," said Ambuj Goyal, IBM's general manager for information management, in a statement.
The acquisition of Solid marks IBM's 12th buyout this year. Most of the deals have resulted in additions to IBM's software business, which accounts for 20% of the company's revenue and 40% of its profits. The largest transaction was IBM's deal to acquire Canadian business-intelligence software vendor Cognos for $5 billion.
Other IBM acquisitions this year include deals to buy Telelogic, DataMirror, WebDialogs, and Princeton Softech.
IBM shares were up 1.76% to $110.60 in early trading Friday.