TSPI vs VBTLX: 1% overlap
TSP I Fund — shown via international proxy and Vanguard Total Bond Market Index Admiral share 1.1% of their portfolios by weight — computed as Σ min(wA, wB) over every holding both funds own.
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
TSPI and VBTLX hold 1 of the same securities. The ten contributing most to the overlap figure:
| Holding | in TSPI | in VBTLX | Δ |
|---|---|---|---|
| CASH | 2.4% | 1.1% | 1.3% |
Where TSPI and VBTLX 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 | TSPI | VBTLX | Δ |
|---|---|---|---|
| Treasuries | 0.0% | 48.2% | −48.2pp |
| Information Technology | 20.9% | 0.0% | +20.9pp |
| MBS Pass-Through | 0.0% | 20.3% | −20.3pp |
| Corporate — industrial & other | 0.0% | 14.6% | −14.6pp |
| Industrials | 13.8% | 0.0% | +13.8pp |
| Financials | 19.7% | 7.9% | +11.8pp |
| Unclassified | 9.1% | 0.7% | +8.4pp |
| Consumer Discretionary | 7.5% | 0.0% | +7.5pp |
Δ is TSPI minus VBTLX, 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
97.6% of TSPI by weight, held in no part of VBTLX.
98.9% of VBTLX by weight, held in no part of TSPI.
A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.
Concentration and cost
| TSPI | VBTLX | |
|---|---|---|
| Top 10 holdings | 16.3% | 71.7% |
| Positions held | 8,453 | 2,047 |
| Cost per $10,000 held, per year | $5 | $4 |
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 TSPI and VBTLX overlap?
TSPI and VBTLX overlap 1.1% by portfolio weight — largely distinct portfolios. They share 1 holdings. The figure comes from current issuer holdings files (TSPI as of 2026-06-30, VBTLX as of 2026-06-30).
How is the overlap between TSPI and VBTLX calculated?
As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If TSPI holds a stock at 6% and VBTLX 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 TSPI and VBTLX?
That depends on your goals — we state facts, not advice. At 1.1% overlap, each fund still contributes meaningfully distinct exposure.
What does TSPI own that VBTLX doesn't?
TSPI holds 8,453 positions and VBTLX holds 2,047; 8,452 of TSPI's positions don't appear in VBTLX at all, and they are 97.6% of TSPI by weight.
You probably hold more than two funds
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Related comparisons
Sources: issuer holdings files, TSPI as of 2026-06-30, VBTLX as of 2026-06-30. Weights are fractions of each fund. Diagnostics, not advice.