Frozen tax bands have claimed many victims, with millions of workers and pensioners dragged into the tax net as their incomes grow.But now thousands more children are falling victim to the unfair system, as their parents miss out on support because of the frozen £100,000 earnings threshold.Families are losing up to £874million of government-funded childcare support as parents' incomes rise above the frozen £100,000 income threshold at which the support is removed, according to new figures.The Department for Education estimates that between 50,500 and 99,000 children were affected by the earnings limit in the last tax year, a Freedom of Information request by Quilter shared with This Is Money shows.As more people earn over £100,000, more families become ineligible for the working parents funded childcare entitlement.Once one parent exceeds the income threshold, they lose their entitlement to tax-free childcare and 30 hours of free childcare.The number of children affected by frozen thresholds has almost quadrupled since 2021, when the freeze on income tax bands was introduced.Families miss out on childcare as the £100,000 earnings threshold remains frozen In 2021, between 13,800 and 27,100 children were thought to be affected, with families losing up to £101million.That figure steadily increased until the 2024-25 tax year, when the estimated number of children affected increased sharply to between 46,400 and 91,300. This meant that up to £469million of government support was no longer available to families.That partly reflects the expansion of childcare support to include younger children. In 2018-2019, working parents of three and four-year-olds could access 15 funded hours a week, which was extended to children aged between nine months and two years old in 2024-25.By 2025-26, eligible children aged between nine months and two years old could access up to 30 hours.While the Department of Education's figures reflect a larger eligible population, they also emphasise the financial consequences related to the £100,000 cliff edge. Had the childcare threshold increased in line with inflation since its introduction, it would have increased to £137,000.