The group, which is steered by chief executive David Wright, has grown through a combination of financial and consumer PR and marketing acquisitions and expansion into Europe, the Middle East and Asia.
Due to the high start-up costs involved the group made a loss of £2.5m ($4.2m) in 2013, down from £4.9m in 2012.
The fourth quarter of 2013 was an important inflection point, when earnings before interest, tax, depreciation and amortisation were positive for the first time.
Porta’s flagship agency, Newgate, had "an exceptional year of growth", according to the group.
This was partly due to the opening of offices in Australia, Hong Kong and Singapore – which Newgate in many cases staffed with former Kreab Gavin Anderson executives.
It was also a result of winning several mandates for IPOs in London in late 2013, a streak the company claims is continuing this year.
Porta’s comms division also includes UK-based agencies in which it recently acquired controlling stakes.
Consumer PR agency Thirteen launched with investment from Porta in September 2013, while corporate and financial PR agency Redleaf Polhill sold a 51 per cent stake to Porta last month.
Porta’s board said its initial strategy of building an international group through start-ups had been successfully completed but it would build critical mass through acquisitions where needed, including in the UK consumer PR space.
"While there will still be some start-up costs as those planned in Qatar and mainland China (Beijing and Shanghai), where we will shortly be advertising for suitable executives, the thrust in the current year will be from a more noticeable balance between organic and acquisition growth."
Porta added it is looking for bolt-on acquisitions for its marketing division, which houses consumer advertising agency Twenty20 Media Vision and financial services advertising and direct marketing agency 21:12.