The takeover of Merian added £16.6bn in Assets Under Management to Jupiter to push total AUM to £58.7bn.
Pre-tax profit at Jupiter rose by 10% to £179m although statutory pre-tax profits fell by 12% to £132.6m due to the cost of the acquisition.
Net outflows were £4 billion for the year, however the company reported gross inflows were "robust" at £16.5 million
Jupiter recently announced it would cut up to 90 jobs as part of a restructure as it beds in Merian.
The ordinary dividend has been held at 17.1 pence per share and a special dividend of 3 pence per share has been proposed.
Jupiter CEO Andrew Formica said that while Covid-19 had caused disruption he was confident the fund manager would see future growth this year.
He said: "This is a year (2020) where we made significant progress against our strategic objectives and laid strong foundations for future growth, despite the disruptive impact on financial markets and businesses brought by Covid-19.
“Throughout this period we also successfully completed the acquisition of Merian on time. This transformational deal has expanded our product and geographic offering while reinforcing our position as a market leader in UK retail. Financially it has exceeded our expectations, delivering greater than expected synergies and already making a significant contribution to group profits.
“While more time is needed to stabilise flows from certain products, these near-term challenges were well-anticipated and factored into the terms of the deal, giving substantial protection to our shareholders.
“Against a backdrop of strengthening investor sentiment and improved momentum as we turn the corner in the battle against Covid-19, I am confident that Jupiter is strongly positioned for future growth."
He said gross inflows were robust at £16.5 billion and the group had seen three consecutive quarters of positive net flows.