Since then, Pimco has installed six deputy chief investment officers in lieu of Mr El-Erian in a move widely seen as removing so-called "key man risk" at the fixed-income specialist. However, concerns have not diminished.
Mr Speich said these developments had directly hurt Allianz's share price this year, which had underperformed both other European insurers and the German stock market.
Addressing the chief executive of Allianz, Michael Diekmann, Mr Speich asked: "What will you do to finally take Pimco out of the negative headlines?"
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Referring to Allianz's insistence that it is best for the German insurer to allow Pimco its autonomy, he added: "Will you now intervene in Newport Beach [Pimco's California headquarters] more strongly?"
Union, a Frankfurt-based asset manager, is Allianz's seventh-largest shareholder, owning 1 per cent of Allianz's shares, according to Bloomberg data.
Other shareholders added their voice to the concerns. Daniela Bergdolt, a spokesperson for DSW, Germany's private shareholder association, said: "I would have preferred if El-Erian had gone more silently and you as a shareholder had intervened more quickly and more clearly.
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"This kind of dispute is something we should have avoided: all of these disputes and quarrels damage not only Pimco but also Allianz."
At the AGM, Mr Diekmann referred to recent speculation that the insurer should interfere more with Pimco but said the recent performance blip at the fixed income investor had to be seen in context of its longer term outperformance of other bond houses.
"There is really no reason to be hard on us," he said.
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Allianz also released preliminary results for the first quarter of the year, showing a drop in net income and operating profit from the same period last year at €1.6bn and €2.7bn respectively despite record quarterly revenues of €34bn.
Assets under management at the asset management arm, which largely consists of Pimco, were unchanged on the quarter at €1.3tn, mainly due to a rise in the market.
Other investors have also expressed their concern over the reputational damage that reports of strife at Pimco may have caused. Yet many analysts believe there is not much that Allianz can do.
Some have raised the issue of whether Allianz would look to sell Pimco, prompting assurances from the company that it remains an integral part of its business.
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Some investors question the wisdom of selling Pimco when the bull market in fixed income has ended. Allianz has also long argued that Pimco's profits from debt trading help offset the German insurer's life insurance division, which struggles when interest rates are low.
While profits at Pimco are falling, they remain strong, contributing about a third of overall operating profit at Allianz last year. "It's a massive cash generating machine that is very capital light," one investor said. "Just because it's going through a soft patch is not a reason to sell."
Union's Mr Speich also raised concerns over Allianz's ability to cope with the low interest environment in Europe, which has particularly affected German insurers that offer life insurance products with hefty guarantees. Allianz was still too reliant on its classic products and was falling behind European rivals Axa, Generali and Zurich in that regard, Mr Speich said.
–By Alice Ross, Financial Times