Deliveroo will price its share sale this week at the lower end of expectations.
The Amazon-backed food delivery app is aiming for a valuation of 7.6 billion pounds - or close to 10.5 billion dollars.
That is less than was expected only a few days ago.
The cautious pricing comes after a string of major UK fund managers said they would not take part in the deal.
Heavyweights including Aberdeen Standard Life, Legal & General and Aviva have all chosen to steer clear.
They cited concern over the firm's gig economy model, which has left it facing criticism over workers' rights.
Some also question the outsized voting rights that will go to company founder Will Shu, and ask whether the loss-making business can ever justify its valuation.
Even so, the deal is said to be covered many times over, and will still be London's biggest IPO in almost a decade.
It's also the biggest ever float for a tech firm on the London Stock Exchange.
Deliveroo shares are due to join the market on Wednesday (March 31).