Any realistic, practical plan to limit tax expenditure cuts to a high-income group would require a phase-in of the cuts or other accommodations, which would add to marginal tax rates, reduce the potential revenue gain, and make the resulting tax change more regressive.

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"He may decide to look at those who have got high levels of wealth, which is actually a bit of a different group to those who have high levels of income, so a mansion tax, for example, for those who have very expensive houses, or looking through things like inheritance tax or capital gains tax, " Mr Johnson says.

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High school students from families at the bottom 20 percent income group are six times more likely to drop out than students from higher-income families.

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The corresponding rate in men in the same group is between one to two times greater in men of the same age in high-income countries.

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The earlier group enjoyed a high degree of mobility but the later one was less fortunate, suggesting that movement between income groups is slowing down.

ECONOMIST: Class

Dubbed the Global High Wealth Industry group, the unit will launch "a small number" of audits of individuals with assets or income in the tens of millions of dollars, Mr. Shulman told an accountants' trade group.

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