The number of trusts and estates fell for the fourth consecutive year in 2017/18 to 149,500.
This represents a 29% drop in the past 12 years since the 220,500 trusts and estates recorded in 2005/06, according to new data from HM Revenue and Customs (HMRC).
In 2013/14, 171,500 trusts and estates made a full self-assessment. This fell to 167,000 in 2014/15, 164,000 in 2015/16 and 159,000 in 2016/17.
Despite the decrease in trusts and estates making self-assessment returns, over £2.7 billion worth of income was created in 2017/18, a 12% increase on the previous year.
The total amount of chargeable gains stood at £3.23 billion with the overall tax bill in 2017/18, for trusts and estates, tipping the scale at £1.32 billion which represented a 5% increase within the year.
49,000 beneficiaries receiving income from their interest in possession trusts made self-assessment returns in 2017/18, a fall of 4,000 returns from the year previous.
Similarly, the number of trusts and estates paying tax at the special trust rate making self-assessments also fell by 4,000 in 2017/18 to 86,500.
Overall, £675 million worth of tax was payable on income of trusts and estates in 2017/18. Of this number, £140 million was taken from interest in possession trusts and £495 million generated from trusts taxed at the special tax rates.
£645 million worth of Capital Gains Tax was made from tax taken from gains in trusts and estates, a 1% increase from the year earlier.
£1.45 billion was taken from gains made on trusts paying tax at the trust rate, representing a 3% fall on 2016/17.
Chargeable gains for interest in possession trusts were £1.45 billion in 2017/18, which was in line with the year previous.
The trust registration service also increased registrations by 22,500 on the previous year, rising to 107,500.
