How far back can you test IJS? To Feb 1985, with DFSVX and NAESX
IJS (US Small Cap Value (S&P 600)) has its own monthly data from Aug 2000. Spliced with DFSVX and NAESX it reaches back to Feb 1985, which adds 15.5 years (37% of the extended history comes from proxies). Data through Sep 2026.
What you'd have missed
- IJS's own data starts in Aug 2000; DFSVX and NAESX extend it to Feb 1985, 15.5 more years.
- Its own history misses the 1987 crash and the 1998 LTCM sell-off.
- Its worst drawdown, -54.1% (May 2007–Feb 2009), is already inside the ETF's own history; the extension does not change the worst case.
- Over the 314 overlapping months DFSVX returned 1.0% a year more than IJS, so the proxy years likely overstate what IJS would have earned by a similar margin.
- VB and VBR are extended with the same NAESX.
How the history is built
IJS (ETF) Aug 2000 → now
DFSVX (DFA U.S. Small Cap Value Portfolio, mutual fund) used Mar 1993 → Jul 2000; its own data runs Mar 1993 → now
NAESX (Vanguard Small-Cap Index Fund, mutual fund) used Feb 1985 → Feb 1993; its own data runs Feb 1985 → now
Feb 1985Sep 2026
Solid bars are the months each fund contributes to the spliced series; the outline shows how far a proxy's own data runs. Each month uses the youngest fund that has data for it; returns are spliced, not prices (dividends reinvested via adjusted close).
How well each proxy tracked IJS
| Proxy | Kind | Months contributed | Overlap with IJS | Correlation | Tracking error | Tracking difference | Beta | Vol ratio | Grade |
|---|---|---|---|---|---|---|---|---|---|
| DFSVXDFA U.S. Small Cap Value Portfolio | mutual fund | Mar 1993–Jul 200089 months | Aug 2000–Sep 2026314 months | 0.981 | 4.23% | +1.03% | 1.03 | 1.05 | Approximate |
| NAESXVanguard Small-Cap Index Fund | mutual fund | Feb 1985–Feb 199397 months | Aug 2000–Sep 2026314 months | 0.959 | 5.80% | -0.68% | 0.91 | 0.95 | Approximate |
| ↳ vs DFSVX (the link it is spliced onto) | Mar 1993–Sep 2026403 months | 0.945 | 6.60% | -1.34% | 0.89 | 0.94 | |||
Statistics are over the months a proxy and IJS both have data. Tracking error is annualized; tracking difference is the annualized geometric gap (positive: the proxy earned more). Page grade: approximate, the worst grade among the proxies that contribute months.
IJS's own history versus the extended history
| The ETF's own history | Proxy years only | Full extended history | |
|---|---|---|---|
| Window | Aug 2000 – Sep 202626.2 years | Feb 1985 – Jul 200015.5 years | Feb 1985 – Sep 202641.7 years |
| Growth of $10,000 | $110,667 | $32,953 | $364,687 |
| CAGR | 9.6% | 8.0% | 9.0% |
| Annualized volatility | 20.4% | 18.9% | 19.8% |
| Sharpe ratio (risk-free 0%) | 0.56 | 0.51 | 0.54 |
| Max drawdown | -54.1%May 2007 → Feb 2009; recovered Apr 2011 | -51.0%May 1986 → Oct 1990; recovered Aug 1993 | -54.1%May 2007 → Feb 2009; recovered Apr 2011 |
| Worst complete calendar year | 2008 (-29.4%) | 1990 (-19.4%) | 2008 (-29.4%) |
| Best complete calendar year | 2003 (39.7%) | 1991 (45.2%) | 1991 (45.2%) |
| Longest underwater (months) | 46 | 86 | 86 |
| Major declines covered | 4 | 2 | 6 |
The columns cover different years, so a higher or lower CAGR is not a verdict on the fund; the point is which market regimes each window includes. Growth of $10,000 is the same one-asset, buy-and-hold calculation the live portfolio app makes.
Growth of $10,000
Drawdowns
How IJS did in each major US stock-market decline since 1985
| Decline | S&P 500 | IJS over the same months | Source of those months |
|---|---|---|---|
| 1987 crashSep 1987–Nov 1987 | -29.8% | -38.8% | NAESX |
| 1998 LTCM sell-offJul 1998–Aug 1998 | -15.3% | -24.4% | DFSVX |
| 2000–02 dot-com bearSep 2000–Sep 2002 | -44.7% | -2.3% | ETF |
| 2007–09 financial crisisNov 2007–Feb 2009 | -50.8% | -51.3% | ETF |
| 2020 COVID crashJan 2020–Mar 2020 | -19.4% | -37.5% | ETF |
| 2022 inflation bearJan 2022–Sep 2022 | -23.9% | -20.2% | ETF |
The decline windows are computed, not chosen: every peak-to-trough fall of at least 15% (month-end) in the S&P 500 series since 1985. The fund's figure compounds its monthly returns from the month after the S&P 500's peak through the trough.
IJS's own five deepest drawdowns (extended history)
| Peak | Trough | Depth | Recovery | Source of the decline months |
|---|---|---|---|---|
| May 2007 | Feb 2009 | -54.1% | Apr 2011 | ETF |
| May 1986 | Oct 1990 | -51.0% | Aug 1993 | NAESX |
| Aug 2018 | Mar 2020 | -40.3% | Jan 2021 | ETF |
| Apr 2002 | Mar 2003 | -31.3% | Nov 2003 | ETF |
| Apr 1998 | Aug 1998 | -28.8% | Feb 2000 | DFSVX |
This covers declines the equity windows miss, such as the bond bear markets of 1994 and 2022.
Caveats
- Before Aug 2000 the returns are DFSVX's, after that fund's own costs; the measured gap while both existed is +1.03% a year.
- Before Mar 1993 the returns are NAESX's, after that fund's own costs; the measured gap while both existed is -0.68% a year.
- Monthly month-end data: intra-month drawdowns were deeper than shown.
- Dividends are reinvested; no taxes or trading costs are modeled.
- Our data source's series for NAESX begins Feb 1985; the fund itself may be older.
Test it yourself
Open IJS as a one-asset portfolio in the live app, where every number recomputes from fresh data.
Open IJS (100%) in the portfolio builder →Used in portfolios: Golden Butterfly, Betterment Core, Larry Portfolio
Used in guides: Betterment Core, Golden Butterfly, Larry Portfolio
Frequently asked questions
- How far back does IJS data go?
- IJS (US Small Cap Value (S&P 600)) has its own monthly data from Aug 2000. Spliced with DFSVX and NAESX it reaches back to Feb 1985, which adds 15.5 years (37% of the extended history comes from proxies). Data through Sep 2026.
- What did IJS do before 2000?
- Before Aug 2000 the series is DFSVX and NAESX's. Those 15.5 years (Feb 1985–Jul 2000) show 8.0% a year with 18.9% annualized volatility and a worst drawdown of -51.0% (May 1986–Oct 1990). In major S&P 500 declines: 1987 crash, -38.8% versus -29.8% for the S&P 500 (NAESX); 1998 LTCM sell-off, -24.4% versus -15.3% for the S&P 500 (DFSVX). The full extended history's worst drawdown is -54.1% (May 2007–Feb 2009).
- How closely does DFSVX track IJS?
- Over 314 overlapping months (Aug 2000–Sep 2026), DFSVX had a correlation of 0.981 with IJS, a tracking error of 4.2% a year and a tracking difference of +1.03% a year (grade: approximate). Over 314 overlapping months (Aug 2000–Sep 2026), NAESX had a correlation of 0.959 with IJS, a tracking error of 5.8% a year and a tracking difference of -0.68% a year (grade: approximate).
Methodology
- Source
- Yahoo Finance via MarketHeist, monthly adjusted close (dividends reinvested). Months run to the last complete calendar month.
- Splice rule
- Each month uses the youngest fund that has data for it; returns are spliced, not prices (dividends reinvested via adjusted close).
- Numbers
- Computed by the MarketHeist portfolio engine as a one-asset, 100% buy-and-hold portfolio, the same calculation the live app makes. Sharpe uses a risk-free rate of 0%. Drawdowns are month-end.
- Correlation
- Pearson correlation of monthly returns over the months both funds have.
- Tracking error
- Standard deviation of the monthly return differences (proxy minus IJS) times the square root of 12.
- Tracking difference
- Annualized geometric return of the proxy minus that of IJS over the overlap. Positive means the proxy earned more.
- Beta and vol ratio
- Beta is the covariance of the proxy with IJS divided by the variance of IJS; vol ratio is the proxy's standard deviation divided by IJS's.
- Grades
- Close: correlation of at least 0.95 and tracking error of at most 3%. Approximate: tracking error of at most 8% and either a cash-like fund (volatility of at most 3%) or correlation of at least 0.80 with a vol ratio of at most 1.25. Category stand-in: anything weaker.
- Generated
- 2026-10-10; data through Sep 2026. Reproduce hash of the full extended one-asset portfolio:
c6a13258e41a10eb
Historical simulation, not investment advice. Past returns, including spliced proxy returns, do not predict future results.