Just been looking at short-term bond ETFs and the SMB vs ISTB comparison is actually pretty interesting from a tax angle. On the surface, ISTB looks better—higher yield, bigger fund, lower fees. But here's the thing: SMB is all municipal bonds, which means federally tax-free income. ISTB covers Treasuries and corporates, so every dollar of interest gets taxed as regular income.

The numbers tell the story. ISTB returned 5.6% in the last year versus SMB's 4.2%, but that gap shrinks fast once you factor in taxes. If you're in a high tax bracket, SMB's tax-free status could actually make the after-tax return higher despite the lower headline yield. ISTB makes more sense in tax-advantaged accounts like IRAs where the tax break doesn't matter anyway.

Performance-wise, both are stable short-duration plays. SMB is narrower—just municipal bonds, 331 holdings—while ISTB spreads across nearly 7,000 bonds. Less diversification with SMB, but that focused approach on tax-exempt income is the real edge for taxable accounts. The choice really comes down to your tax situation, not just raw yield numbers.