Registry rank 1673 · Portfolio as of 2026-02-28
Columbia Mid Cap Index Fund
CMDYX (Columbia Mid Cap Index Fund) · CPXRX (Columbia Mid Cap Index Fund) · NMPAX (Columbia Mid Cap Index Fund) · NTIAX (Columbia Mid Cap Index Fund)
The verdict
What the numbers say
93.9% of this portfolio matches the S&P MidCap 400, which costs $100 a year per $100,000 to own outright. This fund charges $200 a year.
Data provenance
Run 363649da-fcfb-4007-87ef-de06de7710ca; method closet-index@2.0.0; fund accession 0001410368-26-040894; comparison periods and expense-filing links appear with their figures. Machine capture time: 2026-07-29T14:22:09.616Z.
Computed rule checks
1 warning · 1 check clear · 1 unavailable
Check clear
· Rule 1
The fund’s filed benchmark and its closest approved index control point to the same comparison.
Methodology rule · visual rules si-visual-explainers@1.0.0
Warning
· Rule 2
93.9% of this portfolio matches the S&P MidCap 400, which costs $100 a year per $100,000 to own outright. This fund charges $200 a year.
Methodology rule · visual rules si-visual-explainers@1.0.0
Unavailable
· Rule 3
No complete licensed window and filed headline fee are available together for this check.
Computed on licensed market-return history · filed fee as of 2026-02-28
Methodology rule · visual rules si-visual-explainers@1.0.0
Filed fees in dollars
SEC-convention illustration
Computed from SEC filings
Assumptions for each dollar figure: $100,000 starting amount · 5.0% annual return · annual compounding · fees deducted annually · 0.01% computed index-control baseline. Methodology.
| Share class and filing | 10 years | 20 years | 30 years |
|---|---|---|---|
| CMDYX0.20% · SEC expense filing · as of 2026-02-28 | $2,921 | $9,422 | $22,794 |
| CPXRX0.20% · SEC expense filing · as of 2026-02-28 | $2,921 | $9,422 | $22,794 |
| NMPAX0.20% · SEC expense filing · as of 2026-02-28 | $2,921 | $9,422 | $22,794 |
| NTIAX0.45% · SEC expense filing · as of 2026-02-28 | $6,693 | $21,335 | $51,016 |
Real trailing windows
Computed on licensed market-return history
Trailing windows use iShares Core S&P Mid-Cap ETF (IJH) adjusted-close total-return history through 2026-07-29 and the same filed index-control fee baseline as the convention table. Methodology.
| Share class and filing | 10 years | 20 years | 30 years |
|---|---|---|---|
| CMDYXFiled fee as of 2026-02-28 | $4,770Computed on licensed market-return history 2016-07-29 to 2026-07-29 · proxy return 10.88% annualized | $23,049Computed on licensed market-return history 2006-07-31 to 2026-07-29 · proxy return 10.06% annualized | Proxy history begins 2000 — no full 30-year window |
| CPXRXFiled fee as of 2026-02-28 | $4,770Computed on licensed market-return history 2016-07-29 to 2026-07-29 · proxy return 10.88% annualized | $23,049Computed on licensed market-return history 2006-07-31 to 2026-07-29 · proxy return 10.06% annualized | Proxy history begins 2000 — no full 30-year window |
| NMPAXFiled fee as of 2026-02-28 | $4,770Computed on licensed market-return history 2016-07-29 to 2026-07-29 · proxy return 10.88% annualized | $23,049Computed on licensed market-return history 2006-07-31 to 2026-07-29 · proxy return 10.06% annualized | Proxy history begins 2000 — no full 30-year window |
| NTIAXFiled fee as of 2026-02-28 | $10,934Computed on licensed market-return history 2016-07-29 to 2026-07-29 · proxy return 10.88% annualized | $52,246Computed on licensed market-return history 2006-07-31 to 2026-07-29 · proxy return 10.06% annualized | Proxy history begins 2000 — no full 30-year window |
Index-control tracking difference
Annualized fund NAV return minus the matched proxy return. Positive means the fund NAV return was higher over that window.
| Fund NAV class | 10 years | 20 years | 30 years |
|---|---|---|---|
| CMDYX | no exact shared fund NAV/proxy anchors for a full 10-year window | no exact shared fund NAV/proxy anchors for a full 20-year window | no exact shared fund NAV/proxy anchors for a full 30-year window |
| CPXRX | no exact shared fund NAV/proxy anchors for a full 10-year window | no exact shared fund NAV/proxy anchors for a full 20-year window | no exact shared fund NAV/proxy anchors for a full 30-year window |
| NMPAX | no exact shared fund NAV/proxy anchors for a full 10-year window | no exact shared fund NAV/proxy anchors for a full 20-year window | no exact shared fund NAV/proxy anchors for a full 30-year window |
| NTIAX | no exact shared fund NAV/proxy anchors for a full 10-year window | no exact shared fund NAV/proxy anchors for a full 20-year window | no exact shared fund NAV/proxy anchors for a full 30-year window |
These figures are illustrations, not predictions or personalized advice. Returns and fees can differ. Read the research disclaimer.
Change the illustration
Computed from SEC filings
Assumptions for the dollar figures below: $100,000 starting amount; 5.0% annual return; 20 years; annual compounding; fees deducted annually; 0.01% computed index-control baseline. CMDYX SEC expense filing, as of 2026-02-28. Methodology.
| Result | Amount |
|---|---|
| Ending value at baseline | $264,825 |
| Ending value at filed expense ratio | $255,403 |
| Difference attributed to fee drag | $9,422 |
This is an illustration, not a prediction or personalized advice. Returns and fees can differ. Read the research disclaimer.
Largest active differences vs the S&P MidCap 400
The bars are labeled and repeated in the table; color is not the only signal. Linked company names open Buy Like Buffett’s company record; Sensible Investor does not score stocks.
| Holding | Fund | S&P MidCap 400 | Difference |
|---|---|---|---|
| Lumentum Holdings Inc | 1.44% | 0.00% | +1.44% |
| Coherent Corp | 1.18% | 0.00% | +1.18% |
| EchoStar Corp | 0.45% | 0.00% | +0.45% |
| Solstice Advanced Materials Inc. | 0.00% | 0.38% | -0.38% |
| Moog Inc. | 0.00% | 0.26% | -0.26% |
| Caretrust Reit Inc | 0.00% | 0.26% | -0.26% |
| INTERDIGITAL INC | 0.00% | 0.24% | -0.24% |
| SITIME CORP | 0.00% | 0.24% | -0.24% |
| Corebridge Financial Inc | 0.20% | 0.00% | +0.20% |
| United Therapeutics Corporation | 0.63% | 0.80% | -0.17% |
Source and verification
SEC N-PORT filing · filed 2026-04-27 · period 2026-02-28
SEC expense filing · period 2026-02-28
Cite these figures
Each snippet includes the figure’s source-event date and immutable verification URL.
Best-fit active share
Sensible Investor, “Columbia Mid Cap Index Fund — best-fit active share,” 6.1% versus the S&P MidCap 400, fund portfolio as of 2026-02-28; measured against the filed holdings of iShares Core S&P Mid-Cap ETF (IJH), as of 2026-03-31. https://sensible-investor.com/registry/cmdyx/as-of/363649da-fcfb-4007-87ef-de06de7710ca
CMDYX filed expense ratio
Sensible Investor, “Columbia Mid Cap Index Fund — filed expense ratio,” 0.20% for CMDYX, as of 2026-02-28. https://sensible-investor.com/registry/cmdyx/as-of/363649da-fcfb-4007-87ef-de06de7710ca
CMDYX fee per active unit
Sensible Investor, “Columbia Mid Cap Index Fund — fee per unit of active management,” 3.27% using the CMDYX expense ratio as of 2026-02-28 and fund portfolio as of 2026-02-28. https://sensible-investor.com/registry/cmdyx/as-of/363649da-fcfb-4007-87ef-de06de7710ca