Aston Martin, whose cars became famed for their starring role in James Bond films, said the deal would enable it to "invest more than half a billion pounds in new products and a technology programme over the next five years".
The British company said the deal gave the group an enterprise value of 780 million pounds, compared to a value of 630 million pounds prior to the agreement.
It added that no agreement had been made on a technical partnership for Aston Martin with Daimler AG's Mercedes , as some analysts had expected.
Investindustrial said in a statement its stake would come with proportional voting rights and that it expected to receive clearance from competition bodies in the first quarter of 2013.
The Italian group beat Indian tractor maker Mahindra and Mahindra in a two-way battle to invest in the British sportscar maker. Mahindra and Mahindra had been touted as the frontrunner to buy the stake but Investindustrial emerged as the favourite to seal the deal in recent days. Sources told Reuters that Investindustrial was close to sealing a deal.