A virtual public school? That's what K12 does. Over the years, the company has invested roughly $95 million to create an e-learning environment where grade school students get instruction from certified teachers. Now, the company has filed to go public.

K12 has arrangements with public school systems in 16 states. From 2004 to 2007, enrollments increased from 11,000 to 27,000 students. And during this time, revenues went from $71.4 million to $116.9 million.

Parents choose K12 for a variety of reasons, such as geographic constraints, disabilities, the need for faster or slower learning, and even safety concerns of local schools.

So far, the results have been fairly strong. The students test near or above state averages on standardized tests. What's more, based on an internal study of K12 parents, about 97% were "satisfied or very satisfied" and 95% said they would recommend the company to other families.

The lead underwriters on the IPO include Morgan Stanley (NYSE: MS) and Credit Suisse (NYSE: CS). The proposed ticker is LRN.

The IPO prospectus is at the SEC website. Also, check out more recent filings.

Tom Taulli is the author of various books, including the Complete M&A Handbook and the EDGAR-Online Guide to Decoding Financial Statements.