The Bears reported a turnover of £14.3m for the financial year ending September 2016, down from £18.3 million.
Pre-interest and tax profits, known as EBITDA, dropped from £3.7m to £785,761.
But the club say that this was expected to be a lower-profit year due to hosting a relatively unattractive Test match at Edgbaston, against Pakistan in early August, which did not sell out.
Edgbaston accommodated more than 80,000 spectators over the five days of England's Test match win - short of their 25,000 a day capacity.
But they did sell out for both the one-day international against Sri Lanka - and T20 Finals Day.
Chief executive Neil Snowball said: "We expect to see EBITDA* and bottom line revenues grow significantly over the next three years as Edgbaston hosts up to 28 days of major match cricket."
As well as hosting five Champions Trophy games, Warwickshire will again have a Test match this summer, the first ever day-night Test in England against the West Indies, in August.
They will remain T20 Finals Day hosts in 2017 and 2018, when they also host a Test against Sri Lanka.
And, in 2019, they are scheduled to stage an Ashes Test match, as well as five matches in the ICC Cricket World Cup.
"The club is entering one of the most exciting periods in its history," added Snowball. "Our thanks go to our principal stakeholders, the England & Wales Cricket Board and Birmingham City Council.
"Whilst we have an outstanding allocation of major match days in the next three years, we are working hard to develop our off-field commercial opportunities."
*EBITDA stands for Earnings before interest, tax, depreciation and amortisation (the reduction of the value of an asset).
Warwickshire made a pre-tax profit for the 2016 season, but by a reduced amount from their record year in 2015.