The agency, which employs 102 staff across Glasgow, Edinburgh, Aberdeen and Liverpool, hiked earnings to £1.06 million in the year to May 31. Turnover increased 11% to £7.1m, accounts expected to be filed at Companies House next week will show.
Founding director Neil Gibson said: "The growth of the digital side of the business has contributed, but also we have some good growth in Aberdeen, which has consistently been a good performer for us.
"Also, just generally I think [there is] a return of confidence in the market, [and] companies' willingness to spend more on marketing."
He added: "Without being over-optimistic - I think there is a bit to go - there are signs that confidence is returning, and that companies are spending a bit more on marketing, digitial, PR etc."
Mr Gibson, who disclosed that no dividend was paid to directors over the period, said Big had not seen a direct increase in PR spend by companies in relation to the independence referendum.
But he signalled the firm was reaping the benefits of a decision it took to ramp up the digitial services it provides clients several years ago.
Mr Gibson noted: "We took a conscious decision about four or five years ago to invest in people and the general services we offered in that, things like websites, social media, blogging, digital strategy. That investment has paid off because we are now in a position to offer a range of services that complement our traditional offering. That's helped the business considerably over the last few years."
Big said its momentum had continued into its current financial year. It recently announced £500,000 of new account wins and invested £250,000 in switching to a new office in Glasgow, building on earlier moves in Aberdeen and Edinburgh.
Mr Gibson also highlighted its continuing progress in north-west England further to the opening of its Liverpool offices two years ago.
He said: "The north-west is proving a very exciting market for us across all fronts: consumer, corporate and digital. We do hope the office in the north-west will be a significant player for the company going forward."