The 65-strong agency, which ranks in the top half of the PRWeek UK Top 150, started work on the brand last month.
Octopus is responsible for PR execution in the UK and will be help expand its reach into Europe and Asia, as well as working alongside new US agency Bateman Group on content creation for global campaigns.
Hotwire also previously worked for Currencycloud in the US.
Currencycloud provides a payment platform and APIs that can be used by programmers to customise a business' payments systems. Launched in 2012, clients include foreign exchange firm Travelex and e-commerce services provider Klarna.
Helen Aboagye, marketing VP at Currencycloud, said in a statement that Octopus' new 'Brands to Sales' proposition, which launched earlier this year and focuses on accelerating the process of converting marketing activity into sales, was "the perfect fit for a business like ours".