The UK’s so-called £100,000 tax trap is drawing renewed scrutiny after reports that some workers face an effective marginal tax rate of up to 71 percent. The issue arises when higher earners lose key allowances and benefits as their income crosses a defined threshold.
According to reporting from multiple outlets, the structure of the tax system means that individuals earning just above £100,000 can see a sharp increase in their tax burden. This has prompted concern among financial analysts and workers alike, particularly as more people are pushed into higher tax brackets.
The situation has broader implications for work incentives and household finances. According to research cited from wealth manager Killik & Co, a notable share of high earners are reconsidering promotions or pay increases to avoid crossing the threshold.
How the £100,000 Threshold Creates a Steep Marginal Tax Rate
The tax trap is primarily driven by the gradual withdrawal of the personal allowance once income exceeds £100,000. For every £2 earned above this level, £1 of the tax-free allowance is removed. This continues until the allowance is fully eliminated at £125,140.
According to the data, this mechanism results in an effective marginal tax rate of around 60 percent on income within that band. The rate increases further for individuals repaying student loans, where an additional 9 percent deduction can push the total marginal rate to approximately 71 percent.
The financial impact does not stop there. Workers who cross the threshold may also lose access to government-supported childcare. According to the same reporting, parents earning above £100,000 are no longer eligible for up to 30 hours of free childcare per week, a benefit available to those below the limit.
This combination of higher taxation and lost benefits creates what analysts describe as a sharp “cliff edge” in net income. According to Killik & Co, the effect can leave households facing significantly higher costs despite relatively small increases in gross salary.
Evidence Suggests the Tax Trap Is Influencing Career Decisions
Survey data indicates that the tax structure is affecting how individuals approach their careers. According to Killik & Co, more than one in five high earners believe the £100,000 threshold is harming their professional advancement.
The findings show that 10 percent of respondents have considered reducing their working hours to remain below the threshold. A further 17 percent reported they would turn down a promotion or salary increase for the same reason.
Younger workers appear particularly affected. According to the research, over a quarter of individuals aged 18 to 24 said tax considerations had dampened their career ambitions. Analysts suggest this reflects growing awareness of how marginal tax rates can influence take-home pay.
Industry figures have also raised concerns about the wider economic impact. Will Stevens, head of proposition management at Killik & Co, said the tax trap is “actively discouraging” people from increasing their earnings, according to the report.
He added that the situation is pushing some households toward “counterproductive strategies,” including limiting career progression or restructuring income. According to his assessment, this dynamic may weigh not only on individual finances but also on workforce productivity.
At the policy level, there are indications the issue is being reviewed. According to recent statements cited in the reporting, the government has acknowledged that income thresholds linked to childcare support may need simplification, though no specific changes have been outlined.
