Rostrum was brought on board by OB10 following a five-way pitch. The agency is replacing incumbent Chazbrooks Communications.
OB10 is the global B2B e-invoicing network and is operational in more than 90 countries across Europe, North America and Asia.
OB10's customers include HP, IBM, Kellogg's and GlaxoSmithKline. It is in the top third of The Sunday Times Tech Track 100 and in the top ten of Deloitte's Technology Fast 50.
Rostrum will be targeting financial, business and IT press. It will roll out a thought-leadership campaign to increase awareness of the company and aims to 'demystify' electronic invoicing.