Shares in Vodafone jumped 4% in early trade today after the United Arab Emirates-based telecoms company e& revealed it had bought a 9.8% stake in the British mobile operator.
E& was formerly known as Emirates Telecommunications Group.
It said it had no intention of making an offer for the whole of Vodafone and it had spent $4.4 billion to invest at an "attractive valuation" to benefit from a diversification in currencies.
The company said it was fully supportive of Vodafone's board, which has come under pressure from other investors after the group struggled in its mature European markets where competition and regulation have pushed prices lower.
Vodafone chief executive Nick Read has vowed to lead a wave of consolidation in Europe to rebuild markets and boost returns but in recent months he has rejected an approach for the group's Italian assets and missed out on a deal between rivals in Spain.
Shares in Vodafone are down around 25% since Read moved from the finance director role to the top job of CEO in October 2018.
Paolo Pescatore, an analyst at PP Foresight, said the UAE investment was a strong endorsement of Vodafone's strategy and board, despite the failed attempts to strike deals in major markets.
"The move itself will raise eyebrows and may lead to some tension with other shareholders who are keen to see Vodafone consolidate in key markets," he said.
"There will now be opportunities for both Etisalat and Vodafone to work more closely to bring greater efficiencies and launch new products in more products globally," he added.