15-year-old security company Rapid7 completed a major milestone on Friday: a successful IPO.

It raised about $103 million by selling more than 6.45 million shares.

And it opened in Friday above its initial $16 price, popping above $25 by market close, up 58%.

Rapid7, based in Boston, makes corporate computer security tools and is most famous for one called Metasploit that help companies find security holes in their systems, an area called penetration testing.

Metasploit is essentially a collection of all the major security holes in all the major software programs that have been publicly documented. It lets companies think and act like hackers to try and break into their own systems, using the same holes hackers would use.

Rapid7 is the employer of one of the more famous security dudes in that part of the industry, HD Moore, who joined the company when Rapid7 bought Metasploit back in 2009.

Moore had created Metasploit as a free and open source project back in the day, and it quickly became popular with many security hackers contributing to it.

Although terms of that sale were not disclosed, it was one of the first times an open source project was bought by a commercial company and helped prove that free and open source software could grow up to be a bona fide, valuable business.

Moore is the company's chief research officer, but he's not a named officer or major stakeholder, so we have no idea how he fared in today's IPO.

Rapid7's co-founder and chairman, Alan Matthews, with a 10% stake before the IPO, 8% after, did well. He owns just under 3.2 million shares, which were worth nearly $81 million at market close.  

Ex-Microsoftie Corey Thomas, who joined in 2012 as CEO, also did well. His almost $1.2 million shares were worth nearly $31 million at market close.

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