Kinnevik, which is specialised in small to mid-sized companies with growth potential, now owns 26 percent of Zalando, after acquiring the 10 percent stake on Thursday, according to a report in the Financial Times Deutschland newspaper.
The firm, which is controlled by the Stenbeck family, has been buying into the online retailer since 2009.
“Since then we have been following the company’s roaring success,” said Kinnevik chair Mia Brunell Livors.
It has however not been plain sailing for Zalando, with the firm reporting losses for the past two years despite attracting more venture capital than any other German online business.
Zalando is expected to post a turnover of €1.0 billion ($1.3 billion) for 2012.
But with a rapid expansion on the cards, and websites up and running in 14 different countries – including France, UK and Spain, Kinnevik said that it wanted to play an active role in further expansion.
Brunell Livors, who as a member of the advisory board for hugely successful high-street label H&M is no stranger to the business of fashion, said Zalando was one of the most successful online shops in Europe.
The new 10 percent stake that Kinnevik now owns formerly belonged to Holtzbrinck Ventures, Tengelmann Ventures and Rocket Internet – all German companies. Rocket still owns 44 percent of the firm though, making it the biggest shareholder.
Run by three brothers, Marc, Oliver and Alexander Samwer, Rocket Internet was where Zalando begun. It incubates new start-ups until they are ready to operate independently and it is the biggest firm of its kind. Zalando could be the first of their protégé companies to list on the stock market.
Other companies with a share in Zalando include Russian investors Digital Sky Technology, who bought a nine percent stake this year. The firm also owns shares in Facebook and Twitter.
Over the summer, the company received some €40.7 million in loan capital from Commerzbank and a central Thuringia Sparkasse bank.