Customers of broker Hargreaves Lansdown were unable to trade shares on the firm's website as it collapsed under "unprecedented" demand from Royal Mail's IPO.
Investors took to Twitter to complain that they were unable to access the company's website on Friday morning, with many attempting to buy shares as Royal Mail floated on the London Stock Exchange.
One customer said: "Hargreaves Lansdown website has crashed typical on the morning of an important share issue! Royal Mail jumped 36% and I can't do anything!"
Another commented: "Hargreaves Lansdown login system has crashed I hear. They're advising clients to ring. Tempting to suggest they write a letter!"
Financial services firm Hargreaves Lansdown, one of the lead brokers in the Royal Mail float, has around 470,000 customers and holds £36.4 billion of assets for clients.
According to an employee of the firm, head of pensions research Tom McPhail, the Hargreaves Lansdown website has suffered "intermittent" outages throughout the morning, due to "unprecedented" demand as a result of the Royal Mail IPO. He added that the company has increased the number of employees supporting its service.
"We've more than doubled dealing staff throwing all resources we can at executing client trades," McPhail tweeted.
The company later apologised via its official Twitter account, adding that it is possible in some cases to make trades via phone.
"All available staff are working on dealing lines and website, we are trading by phone but delays getting through, our sincere apologies," the firm said.
Hargreaves Lansdown was unable to provide any further information at this time.
Commenting on the outage, Mark Baxter, director as specialist IT recruiter Greythorn said that the broker has damaged its reputation by not bringing in more IT expertise ahead of the high profile IPO.
"I'm surprised Hargreaves Lansdown didn't draft in some temporary IT specialists to deal with any issues given how important online share dealing is in an IPO," Baxter said.
"It shows extremely poor planning in the IT department given how well known it was that the shares were oversubscribed. They'll lose a lot of customers and a great deal of reputation through failing to recognise the risks and take appropriate measures."
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