Celtic's income in the first half of the season almost doubled compared to the previous year, according to the club's interim report.
Revenue for the second half of 2016 was £61.2m, an increase of 95 per cent on the same period in 2015. The latest figure was higher than group revenue for the whole of last season (£52m).
Celtic's qualification for the Champions League group stages helped them make a pre-tax profit of £18.6m over six months, a rise of almost £7m in the previous season, when Celtic competed in the Europa League groups.
The report reveals the club spent £9.5m on transfers during the summer. Manager Brendan Rodgers brought in Moussa Dembele, Scott Sinclair, Cristian Gamboa and Dorus de Vries. The Scottish champions received £2m after selling Stefan Johansen to Fulham.
Celtic reported money in the bank of £18.6m at the end of the year, up almost £11m in 12 months.
Chairman Ian Bankier wrote: "The board is optimistic about our immediate future and firmly supports the self-sustaining financial model that has served us well.
"We continue to seek to influence developments in domestic and European football through representation on the board of the Scottish Professional Football League, the European Club Association executive board and the UEFA Club Competitions Committee.
"Looking forward, and entirely in line with our trading seasonality, we do not expect the same level of financial performance in the second half of 2017.
"In this period we will play fewer home fixtures and no European games."