It is issuing 1.89mln new shares at an 80p placing price.
Some 1.64mln shares have been bought by existing and new institutional shareholders, while 250,000 shares were picked up by the company’s executive directors.
Andrea Stecconi, Defenx chief executive, bought 218,750 new shares to increase his holding to 21.2% of the company.
In a stock market statement, Stecconi said: “We are very pleased by the support shown by both existing and new shareholders in the placing.
“These funds will enable us to accelerate the development of our software, both to enhance existing products and to develop and test new products.
“These products are being developed in response to customer demand and this fund raising will ensure we can bring new products and features to the market quicker than previously envisaged."