Security MSP and incident response firm ECSC has raised £5.9m after launching on the AIM market of the London Stock Exchange.
Bradford-based ECSC announced its intention to IPO last week, alongside plans to open a London office and increase headcount from 50 to 200 by the end of 2018.
Speaking to CRN, CEO Ian Mann said he has turned down a number of takeover approaches in recent years, but chose to go public because of the credibility that being a public company brings.
"In the last few years we've had a number of serious offers to buy the business but we decided that - although some of those financials made sense, especially for the shareholders - we think that our independence counts for a lot and it counts for a lot for our clients," he said.
"We've raised all the money that we've wanted to raise and we do think that the transparency and accountability you have as a public company is quite important.
"What we do requires a high level of trust and we think that the fact we've been doing this for years, our blue chip client base, and being a public company means we're in a good position."
ECSC shares surged by a fifth today, its first day of trading, starting at 167 pence and rising to 200 pence.
ECSC does not disclose its revenue figures on Companies House, but Mann told CRN that in its last financial year the firm recorded a turnover of £3.5m - an increase of 22 per cent on the previous year.
Mann said he has ambitions to grow the company's turnover by 20 per cent a year over the next few years as it looks to expand the business it already does in the 25 European countries it already works in - while its first foray in Australia is also on the cards.
"We've been planning this for two years and we've got a very detailed development plan," he said.
"The risk tends to come if you're going into new products or new regions or something like that, but for us we have a strong track record of profitable growth in the UK and our plan is to expand what we already do.
"It really is replicating and growing what is a proven model, not about developing a new fancy technology or moving into a new geographic region so we think we've got a model that reduces risks - and the fact that we've had a good reception from the City and had a good response from investors shows that we have a good model."