After taking a stake in location-based mobile ad firm Acuity Mobile last year, Nokia’s own mobile mapping and ad unit NAVTEQ, has followed up with an outright acquisition. Financial terms were not disclosed, but an SEC filing reveals that NAVTEQ’s initial stake was worth at least $2.8 million. Acuity had raised $1 million in funding from unnamed investors in 2007.

NAVTEQ had been licensing Acuity’s technology, which covers SMS, mobile web and app-based ads, for a number of years; the companies declined to comment on whether Acuity Mobile will retain its own branding or be folded into NAVTEQ (NYSE: NVT). Release.

• NAVTEQ Takes Stake In Acuity Mobile
• Location-Based Mobile Ad Firm Acuity Mobile Gets Funding