Investment into new products and services means G4S PLC (LON:GFS) expects full-year profits to be flat on last year.
The FTSE 250 group manages cash for companies and banks including guarding and security, as well as running prisons and detention centres on behalf of the government.
READ: G4S slumps as it posts 36% drop in first-half profits after raft of disposals
Organic revenues rose 2.5% in the three months ended September 30, compared with 0.2% in the first half.
That was driven by “strong” performances in security services in North America and Asia as well as by healthy demand for its new technology-enabled cash solutions, which more than offset lower revenues in Benelux and conventional cash services.
Chief executive Ashley said that the business has “good momentum” going into 2019.
“Our revenue growth, favourable sales mix and productivity programmes underpin our PBITA for 2018 which, after investment in new products and services, we expect to be in line with 2017 on a constant currency basis," he added.
Shares fell 9.5% to 195.8p.