BERLIN, Germany — Shares in German e-commerce investor Rocket Internet took another tumble on Thursday as concerns grew over the worth of its portfolio after a cut in the valuation of its online clothing sites operating in emerging markets.

Rocket and co-investor Kinnevik said on Wednesday a new funding round for Global Fashion Group (GFG) gave it a valuation of 1 billion euros ($1.14 billion), a third of the figure put on the business when it last raised funds in August.

That prompted questions about the true worth of Rocket's other companies, which it bases on fund raising with third-party investors — a measure it calls "last portfolio value" — rather than the net asset value (NAV) measure used by most funds.

"The GFG valuation cut reflects the changing dynamic with regard to valuing e-commerce business models and also a lack of conservativism in Rocket's valuation methodology," said Jefferies analyst David Reynolds, who rates Rocket "hold."

Kinnevik has long put more conservative valuations on firms it jointly holds with Rocket. On Wednesday, it reported a lower NAV figure for furniture site Home24, while lifting the number for other e-commerce businesses Westwing, Linio and Lazada.

However, there was still a discrepancy of more than €1 billion between the Kinnevik valuations and those given by Rocket for Home24, Westwing and Linio as of March 31.

Founded in Berlin by brothers Oliver, Alexander and Marc Samwer in 2007, Rocket has set up dozens of e-commerce sites, aiming to replicate the success of Amazon and Alibaba in Africa, Southeast Asia, Latin America and Russia.

But Europe's top Internet investor has faced increasing disquiet from investors about the scale of the losses at start-ups ranging from online fashion to food delivery, as well as delays to planned stock market listings.

On Thursday, Bank of America Merrill Lynch, which advised on Rocket's initial public offering in October 2014, cut the stock to "underperform", citing downgrades in its operating companies and a soft private equity funding environment.

Shares Down a Quarter this Year

Sentiment was not helped by a report that Rocket's fintech company Paymill has filed for what its founder Mark Henkel told Germany's Gruenderszene news website was a "strategic insolvency" to win more time to find a buyer for the business.

Rocket did not immediately make managers available to comment.

Rocket's shares, which already dropped 14 percent on the GFG valuation news on Wednesday, fell another 8.5 percent by 1110 GMT to €21.07, while Kinnevik was off 2.1 percent.

Rocket's shares are now down more than a quarter this year to give them a market capitalisation of €3.8 billion and are half the €42.50 offer price in its IPO. BoAML gave a new price target for the stock of €19.

Last September, Rocket said its portfolio based on LPV was worth €6 billion, which it said equated to €44 per share including net cash of €1.2 billion, compared to €32 at its IPO.

However, Rocket did not highlight the LPV valuation earlier this month when it reported annual results for 2015, with chief executive Oliver Samwer saying he wants to focus on operational metrics like revenue and profit now the firms are more mature.

Samwer said then Rocket was on track to make three of its start-ups profitable by the end of 2017, and said its losses should have peaked last year when its companies burned through €1 billion.

By Mia Shanley and Emma Thomasson; additional reporting by Alasdair Paul and Nadine Schimroszik; editor: David Evans.