VFIAX vs VTWNX: 18% overlap

Vanguard 500 Index Admiral and Vanguard Target Retirement 2020 share 18.2% 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 — VTWNX as of 2026-03-31, the rest through 2026-06-30. Each fund is compared using its most recent file, so any trading in between shows up as a difference.

Hold both, 50/50
1.8Effective Funds

You would hold two tickers and get the diversification of 1.8. Two funds that shared nothing would score 2.0; two identical funds score 1.0.

Overlap
18.2%
VFIAX expense ratio
0.04%
VTWNX expense ratio
0.08%

Top shared holdings

VFIAX and VTWNX hold 503 of the same securities. The ten contributing most to the overlap figure:

Holdingin VFIAXin VTWNXΔ
NVDA7.5%1.3%6.2%
AAPL6.6%1.2%5.4%
MSFT4.3%0.8%3.5%
AMZN3.6%0.6%3.0%
GOOGL3.2%0.6%2.7%
AVGO2.8%0.5%2.3%
GOOG2.6%0.5%2.1%
MU2.0%0.4%1.7%
META1.9%0.3%1.6%
TSLA1.8%0.3%1.5%

Where VFIAX and VTWNX 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.

SectorVFIAXVTWNXΔ
Unclassified0.0%29.8%29.8pp
Information Technology38.0%10.0%+28.0pp
Treasuries0.0%17.1%17.1pp
Communication Services9.7%2.3%+7.4pp
MBS Pass-Through0.0%7.2%7.2pp
Consumer Discretionary9.3%2.9%+6.4pp
Health Care8.9%2.7%+6.2pp
Corporate — industrial & other0.0%5.5%5.5pp

Δ is VFIAX minus VTWNX, 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

Only in VFIAX
2 positions

0.1% of VFIAX by weight, held in no part of VTWNX.

Only in VTWNX
16,180 positions

80.2% of VTWNX by weight, held in no part of VFIAX.

A large count with a small weight is the usual shape: the positions one fund adds are typically its smallest ones.

Concentration and cost

VFIAXVTWNX
Top 10 holdings36.4%44.9%
Positions held5057
Cost per $10,000 held, per year$4$8

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 VFIAX and VTWNX overlap?

VFIAX and VTWNX overlap 18.2% by portfolio weight — moderate overlap. They share 503 holdings. The figure comes from current issuer holdings files (VFIAX as of 2026-06-30, VTWNX as of 2026-03-31).

How is the overlap between VFIAX and VTWNX calculated?

As the sum of the smaller weight in each fund, over every holding both funds own: Σ min(wA, wB). If VFIAX holds a stock at 6% and VTWNX 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 VFIAX and VTWNX?

That depends on your goals — we state facts, not advice. At 18.2% overlap, each fund still contributes meaningfully distinct exposure.

What does VFIAX own that VTWNX doesn't?

VFIAX holds 505 positions and VTWNX holds 7; 2 of VFIAX's positions don't appear in VTWNX at all, and they are 0.1% of VFIAX by weight.

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Related comparisons

Sources: issuer holdings files, VFIAX as of 2026-06-30, VTWNX as of 2026-03-31. Weights are fractions of each fund. Diagnostics, not advice.