Shares in GlobalData dropped 17% to 54.2p on Monday after the data and analytics group signalled that a push to revive revenue growth would weigh on profit margins for years to come.
GlobalData, an AIM-listed company that sells business intelligence and market data across healthcare and other sectors, reported half-year results broadly in line with City forecasts.
Revenue grew 4% to give earnings before interest, tax, depreciation and amortisation of £54.8 million, and underlying growth ran at 1% across both its main divisions.
The share price fall instead reflected the cost of the company's plans to reaccelerate that growth.
GlobalData has launched a wide-reaching artificial intelligence programme to automate workflows and speed up delivery of its data, while continuing to invest in its sales teams.
Broker Panmure Liberum said the reinvestment would hold back the rebuild of profit margins, and cut its group forecasts accordingly.
The broker reduced its expected earnings before interest, tax, depreciation and amortisation by about 12% across its forecast horizon, trimming margins by roughly five percentage points.
It also lowered its estimate for this year's fully diluted earnings per share by around 25%.
Panmure cut its target price to 100p from 140p, though it kept its buy rating on the stock.
The broker argued that the shares looked cheap even on the reduced numbers, trading well below the average of a peer group that includes RELX, Experian and Pearson.
There were brighter spots in the results.
The consumer arm grew 7% in the first half, helped by lower customer losses, higher pricing and wins against rivals, and a new inside sales team has begun to cut churn among smaller clients.
Value renewal rates, a measure of how much existing customers spend when they renew, rose two percentage points to 91%.
The healthcare division, which recently absorbed the Cambridge Healthcare acquisition, delivered reported revenue growth of 8.8%.
Panmure said margin expansion should follow once the growth investment starts to pay off, describing the more cautious forecasts as improving the balance of risks from here.
The shares had climbed steadily earlier in the year before sliding back over the summer.
