For individuals approaching retirement, the decision to convert a traditional IRA to a Roth IRA involves a complex calculation of current versus future tax brackets. With a portfolio of $950,000, a full conversion would trigger a significant immediate income tax bill, as the entire amount would be treated as taxable income in the year of the conversion.

Financial planners generally suggest that a Roth conversion is most beneficial if the account holder expects to be in a higher tax bracket during retirement than they are currently, or if they wish to avoid Required Minimum Distributions (RMDs) that begin at age 73. Because Roth IRAs do not require RMDs during the owner's lifetime, they offer more flexibility for legacy planning and can reduce the tax burden on heirs.

However, the primary risk is the 'tax hit.' By paying taxes on the $950,000 now, the couple would reduce the total amount of capital available to compound over the remaining years of their investment horizon. If the couple intends to use these funds to cover immediate living expenses in the near future, the liquidity required to pay the conversion tax could significantly deplete their retirement nest egg. Experts often recommend a 'partial conversion' strategy, where the couple converts smaller amounts over several years to stay within a lower tax bracket, rather than executing a single, large-scale conversion that could push them into the highest marginal tax rate.