One of the UK’s largest fund managers will not buy shares in Deliveroo when it goes public because of concerns over the rights of its delivery riders.

David Cumming, chief investment officer at Aviva Investors, which has £365bn assets under management, said it will avoid Deliveroo’s initial public offering for several reasons, and workers’ rights “is one of them”.

Deliveroo is planning to go public in London at a valuation of £8.8bn.

Its 100,000 riders are deemed to be independent contractors and are paid by the number of meals they deliver rather than a hourly wage. The classification means that they are not deemed to be full-time employees so do not benefit from certain workers’ rights.

Cumming said there was a “combination of investment risk and social issues that affect our judgment whether the shares are a buy or not”.

He told BBC Radio 4’s Today: “A lot of employers could make a massive difference to workers’ lives if they guaranteed working hours or a living wage, and how companies behave is becoming more important.”

He pointed to the “investment risk if the legislation changes” and Deliveroo’s riders are reclassified as workers.

Andrew Millington, head of UK Equities at Aberdeen Standard, told ITV News that his firm would not buy the shares, because “we are concerned about the sustainability of the business model, including but not limited to its employment practices, and also the broader governance of the business”.

Deliveroo revealed in its flotation prospectus that it faces investigations across Europe over the legal status of its riders, and warned that it might have to rewrite its business model if it was forced to provide them with holiday and sick pay, minimum wages and other benefits.

A spokesman said: “Deliveroo riders are self-employed because this gives them the freedom to choose when and where to work. We are confident in our business model, which has been upheld by UK courts three times, including the High Court twice.”

The status of so-called gig workers was recently boosted by a decision of the UK Supreme Court, which determined that Uber drivers, who did not receive full workers’ rights, should be classified as workers.