What: Following several post-earnings sell-offs this year, one billionaire investor apparently believes cybersecurity solution company Imperva (NYSE: IMPV) has reached bargain territory. Shares jumped as much as 11.6% on Tuesday after a 13D filing with the Securities and Exchange Commission revealed activist billionaire investor Paul Singer made a major investment in the company.

Image source: Imperva.

So what: Singer and his associate's funds collectively now have a combined stake of approximately 9.8% of Imperva's common stock. The position was revealed in the 13D filing after market close on Monday. The filing noted that the investors "believe the securities of the Issuer are materially undervalued." It also said:

The Reporting Persons believe the Issuer operates in a highly strategic area of the technology industry with an attractive competitive position and a compelling product set in both the web application firewall and database activity monitoring markets, the value of which is not reflected in the Issuer's current market value. The Reporting Persons believe there are both strategic and operational opportunities for the Issuer that would meaningfully increase value to shareholders and have initiated a dialogue with the Issuer's Management and Board of Directors (the "Board") regarding those opportunities.

Now what: It's worth emphasizing that the outcome of an activist investor's efforts is never certain to be a positive one. Investors may benefit from keeping an eye on any updates from the activist investment, but they should prioritize their own due diligence of the company's fundamentals.