MUB vs SWTSX: 0% overlap
iShares National Muni Bond ETF and Schwab Total Stock Market Index share 0.0% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
Different holding dates. These holdings were published about 3 months apart — SWTSX as of 2026-04-30, the rest through 2026-07-23. Each fund is compared using its most recent file, so any trading in between shows up as a difference.
You would hold two tickers and get the diversification of 2.0. Two funds that shared nothing would score 2.0; two identical funds score 1.0.
Top shared holdings
MUB and SWTSX hold 1 of the same securities. The ten contributing most to the overlap figure:
| Holding | in MUB | in SWTSX | Δ |
|---|---|---|---|
| CASH | 0.0% | 0.1% | 0.1% |
Where MUB and SWTSX differ
Sector weights as a share of each fund, ordered by the size of the gap rather than the size of the sector — two funds that overlap heavily still usually diverge somewhere.
| Sector | MUB | SWTSX | Δ |
|---|---|---|---|
| Information Technology | 0.0% | 32.3% | −32.3pp |
| State Tax-Backed | 30.7% | 0.0% | +30.7pp |
| Local Tax-Backed | 14.9% | 0.0% | +14.9pp |
| Utilities | 16.8% | 2.3% | +14.5pp |
| Financials | 0.0% | 11.9% | −11.9pp |
| School Districts | 10.2% | 0.0% | +10.2pp |
| Transportation | 10.2% | 0.0% | +10.2pp |
| Communication Services | 0.0% | 10.1% | −10.1pp |
Δ is MUB minus SWTSX, in percentage points. Sector data is not published by every issuer, so “Unclassified” is a real category rather than a gap in the table.
What each fund holds alone
101.0% of MUB by weight, held in no part of SWTSX.
99.7% of SWTSX by weight, held in no part of MUB.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| MUB | SWTSX | |
|---|---|---|
| Top 10 holdings | 17.2% | 33.9% |
| Positions held | 969 | 2,939 |
| Cost per $10,000 held, per year | $5 | $3 |
Cost is the expense ratio applied to $10,000; it excludes any brokerage commission, bid-ask spread or tax consequence. Figures are facts about the funds, not a suggestion about which to hold.
Frequently asked
How much do MUB and SWTSX overlap?
MUB and SWTSX overlap 0.0% by portfolio weight — largely distinct portfolios. They share 1 holdings. The figure comes from current issuer holdings files (MUB as of 2026-07-23, SWTSX as of 2026-04-30).
How is the overlap between MUB and SWTSX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If MUB holds a stock at 6% and SWTSX holds the same stock at 4%, 4% counts as shared. The result is bounded between 0% and 100%, and it is computed after looking through any fund-of-funds to the underlying holdings.
Is it redundant to hold both MUB and SWTSX?
That depends on your goals — we state facts, not advice. At 0.0% overlap, each fund still contributes meaningfully distinct exposure.
What does MUB own that SWTSX doesn't?
MUB holds 969 positions and SWTSX holds 2,939; 967 of MUB's positions don't appear in SWTSX at all, and they are 101.0% of MUB by weight.
You probably hold more than two funds
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Related comparisons
Sources: issuer holdings files, MUB as of 2026-07-23, SWTSX as of 2026-04-30. Weights are fractions of each fund. Diagnostics, not advice.