Rumors have been swirling that IBM will be acquiring database security company Guardium after the Israeli financial newspaper, The Market, reported the acquisition yesterday (translated version here). Big Blue is reportedly shelling out $225 million for Israel-based Guardium. This year alone, IBM has acquired six companies, including RedPill Solutions, SPSS, Ounce Labs, Exeros and Outblaze.

A subsidiary of Log-On Software, Guardium provides technologies that ensure security of enterprise databases. The startup protects databases for Microsoft, IBM, Oracle, Sun Microsystems and other companies. The Market reports that Guardium is profitable, with sales in the tens of millions per year.

Guardium, which was founded in 2002, has raised a total of $21 million in funding from Cisco, Cedar Fund, Ascent Venture Partners, Stage One Ventures, Veritas Venture Partners and others. IBM is furthering its strategy of investing in systems software for the enterprise, as opposed to hardware.

IBM refused to comment on the acquisition of Guardium but the deal is expected to close in the next few days.