Wedged between the strong debuts this week of two tech companies, Proofpoint has put in its paperwork to refill the IPO pipeline. The subscription-based email security vendor filed for a rather small $50m offering, which is being led by Credit Suisse and Deutsche Bank. Earlier this week, Jive Software hit the market well above its expected price while Zynga raised a cool $1bn as it priced its offering at the top end of its range.

Founded in 2002 by a former Netscape executive, Proofpoint has expanded beyond its core email security. Most recently, we noted that the company has begun to position itself as a full compliance platform, complete with email discovery and litigation support. While Proofpoint’s technology is solid, Wall Street may be left wanting a bit more from its financials.

For starters, Proofpoint has never printed black numbers, and has wrung up a total of $155m in accumulated deficit. Meanwhile on the top line, the company increased revenue a less-than-stellar 27% through the first three quarters of 2012. That compares to 43% growth in sales over the same period at Imperva, the most recent security vendor to hit the public market. Proofpoint plans to trade on the Nasdaq under the ticker PFPT.