Shares in the polling company YouGov plunged by almost half on Thursday after the UK research and analytics company warned that sales and profits would be lower than expected this year.

The firm, which is best known for its political polling but generates most of its revenues from providing consumer data and analysis to businesses, said sales bookings had been lower than anticipated since it reported half-year figures in late March.

As a result, YouGov now expects revenues this year to be between £324m and £327m, while adjusted operating profit is expected to come in between £41m and £44m. This is below the estimates of analysts, who had been forecasting revenues of £341m and profits of £67m.

The shares fell 46% to 440p, giving the company a market value of about £510m. Last year, it was worth more than £1bn.

The company, which has a panel of more than 27 million people globally who sign up to take its surveys, said demand was slow in Europe, the Middle East and Africa, in particular Germany, Austria and Switzerland.

While demand for customised research has gone up, sales in YouGov’s data products division have remained slow, with fast-turnaround research services continuing to decline.

“Casual observers of YouGov might assume the company would enjoy a bumper time during the election but its polling operation makes a relatively modest contribution to group revenue,” said Russ Mould, investment director of the stockbroker AJ Bell.

“The data analytics side is more important and this is where the company is struggling. The company invested for an expected acceleration of growth in the second half of its financial year which, in classic fashion, failed to materialise.

“This may reduce some of the clamour for the company to move its listing to the US in search of a higher rating. The one reassuring element of the announcement is the recently acquired consumer panel business is performing as expected.”

Last year, Stephan Shakespeare, who moved from chief executive to chair of the firm he set up with the former chancellor Nadhim Zahawi in 2000, said YouGov was considering moving its listing to the US, its largest market, where it works with technology companies and consumer brands.

In January, YouGov bought GfK’s consumer panel services business, the German company’s household purchase data division, which increased YouGov’s size in the US by 50%. It said on Thursday that the business was doing well, although some of its contribution will shift slightly into next year.

YouGov invested £6m in technologies in the first half of the year, up from £4.4m a year earlier, and launched its first artificial intelligence product to meet growing demand in qualitative research.

It said it would focus on streamlining the business to save money and prioritise investment in key growth areas such as upgrading data products, expanding its AI capabilities and improving its sales operation.