Tax Efficiency of Investments

Which wrapper an asset belongs in is the asset-location question, covered at section “Individual Retirement Arrangements (IRAs)” and refined at section “Asset Location: Two Refinements That Change the Answer”. What follows is the parameter that quantifies it.

Quantifying Tax Efficiency ($\mathrm{\Delta }$)

To optimize your portfolio, use the tax drag parameter $\mathrm{\Delta }$. This parameter measures the proportion of an asset’s tax-free return, $r$, that is preserved after accounting for annual taxes in a taxable account:

Where:

• $\mathrm{\Delta }=1.0$ represents complete tax immunity (e.g., municipal bonds or assets held in a Roth IRA).
• Lower values of $\mathrm{\Delta }$ represent high tax drag, common in high-yield debt or active funds in taxable accounts.

To maximize your wealth, direct your contributions to keep $\mathrm{\Delta }$ as close to 1.0 as possible by coordinating asset location with account wrappers, as detailed in section “Tax Diversification”.