London and New York-based TagMan has closed its latest venture capital funding round with help from its existing backers.

The company, which helps advertisers and marketers monitor advertisement campaigns online, has now totalled venture capital investments of $13.6 million.

The first investor to back TagMan was Cambridge Business Angels through a $1.3 million round back in February 2010.

TagMan’s new funding will be put to use in growing its global partnership program, STREAM, which provides access to tags as well as data collection and cross-channel marketing analysis.

Jon Baron, CEO of TagMan, comments, ‘We are excited to deepen our relationship with our investors as we rapidly expand our customer and partner portfolios.

‘This year we have welcomed several major additions to our global list of clients with new accounts across retail, travel and hospitality, and financial services sectors.’

The 2013 customer wins for TagMan include Seatwave, Sovereign and Travix, which now sit alongside existing clients such as Spotify, John Lewis and Tesco Mobile.

American investor Greycroft Partners, which counts The Huffington Post and Skimlinks as investments, has now been part of three TagMan funding rounds.

Ian Sigalow, partner at the firm, says, ‘TagMan’s focus on facilitating beneficial relationships between marketers and their vendors is resonating with the entire digital marketing ecosystems.

‘In the three years since Greycroft first invested, TagMan has become the undisputed leader in Tag Management System, marketing data, and marketing attribution.’