How far back can you test IEF? To Feb 1985, with VFITX and FGOVX
IEF (Intermediate Treasuries (7-10y)) has its own monthly data from Aug 2002. Spliced with VFITX and FGOVX it reaches back to Feb 1985, which adds 17.5 years (42% of the extended history comes from proxies). Data through Sep 2026.
What you'd have missed
- IEF's own data starts in Aug 2002; VFITX and FGOVX extend it to Feb 1985, 17.5 more years.
- Its own history misses the 1987 crash and the 1998 LTCM sell-off, and only partly covers the 2000–02 dot-com bear.
- Its worst drawdown, -23.2% (Jul 2020–Oct 2023), is already inside the ETF's own history; the extension does not change the worst case.
How the history is built
IEF (ETF) Aug 2002 → now
VFITX (Vanguard Intermediate-Term Treasury Fund, mutual fund) used Nov 1991 → Jul 2002; its own data runs Nov 1991 → now
FGOVX (Fidelity Government Income Fund, mutual fund) used Feb 1985 → Oct 1991; 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 IEF
| Proxy | Kind | Months contributed | Overlap with IEF | Correlation | Tracking error | Tracking difference | Beta | Vol ratio | Grade |
|---|---|---|---|---|---|---|---|---|---|
| VFITXVanguard Intermediate-Term Treasury Fund | mutual fund | Nov 1991–Jul 2002129 months | Aug 2002–Sep 2026290 months | 0.982 | 2.23% | -0.28% | 0.69 | 0.71 | Close |
| FGOVXFidelity Government Income Fund | mutual fund | Feb 1985–Oct 199181 months | Aug 2002–Sep 2026290 months | 0.961 | 2.79% | -0.79% | 0.62 | 0.65 | Close |
| ↳ vs VFITX (the link it is spliced onto) | Nov 1991–Sep 2026419 months | 0.959 | 1.40% | -0.40% | 0.87 | 0.91 | |||
Statistics are over the months a proxy and IEF both have data. Tracking error is annualized; tracking difference is the annualized geometric gap (positive: the proxy earned more). Page grade: close, the worst grade among the proxies that contribute months.
IEF's own history versus the extended history
| The ETF's own history | Proxy years only | Full extended history | |
|---|---|---|---|
| Window | Aug 2002 – Sep 202624.2 years | Feb 1985 – Jul 200217.5 years | Feb 1985 – Sep 202641.7 years |
| Growth of $10,000 | $22,048 | $42,775 | $94,311 |
| CAGR | 3.3% | 8.7% | 5.5% |
| Annualized volatility | 6.7% | 5.0% | 6.0% |
| Sharpe ratio (risk-free 0%) | 0.53 | 1.71 | 0.92 |
| Max drawdown | -23.2%Jul 2020 → Oct 2023; not yet recovered | -9.3%Oct 1993 → Nov 1994; recovered May 1995 | -23.2%Jul 2020 → Oct 2023; not yet recovered |
| Worst complete calendar year | 2022 (-15.2%) | 1994 (-4.5%) | 2022 (-15.2%) |
| Best complete calendar year | 2008 (17.9%) | 1995 (20.5%) | 1995 (20.5%) |
| Longest underwater (months) | 74 | 20 | 74 |
| Major declines covered | 3 + 1 partly | 2 + 1 partly | 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 IEF did in each major US stock-market decline since 1985
| Decline | S&P 500 | IEF over the same months | Source of those months |
|---|---|---|---|
| 1987 crashSep 1987–Nov 1987 | -29.8% | 1.7% | FGOVX |
| 1998 LTCM sell-offJul 1998–Aug 1998 | -15.3% | 3.4% | VFITX |
| 2000–02 dot-com bearSep 2000–Sep 2002 | -44.7% | 31.3% | partly VFITX |
| 2007–09 financial crisisNov 2007–Feb 2009 | -50.8% | 17.1% | ETF |
| 2020 COVID crashJan 2020–Mar 2020 | -19.4% | 10.5% | ETF |
| 2022 inflation bearJan 2022–Sep 2022 | -23.9% | -15.6% | 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.
IEF's own five deepest drawdowns (extended history)
| Peak | Trough | Depth | Recovery | Source of the decline months |
|---|---|---|---|---|
| Jul 2020 | Oct 2023 | -23.2% | not yet recovered | ETF |
| Oct 1993 | Nov 1994 | -9.3% | May 1995 | VFITX |
| Apr 2013 | Dec 2013 | -7.6% | Nov 2014 | ETF |
| Jul 2016 | Apr 2018 | -7.2% | May 2019 | ETF |
| Dec 2008 | Jun 2009 | -6.7% | Jun 2010 | ETF |
This covers declines the equity windows miss, such as the bond bear markets of 1994 and 2022.
Caveats
- Before Aug 2002 the returns are VFITX's, after that fund's own costs; the measured gap while both existed is -0.28% a year.
- Before Nov 1991 the returns are FGOVX's, after that fund's own costs; the measured gap while both existed is -0.79% 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 FGOVX begins Feb 1985; the fund itself may be older.
Test it yourself
Open IEF as a one-asset portfolio in the live app, where every number recomputes from fresh data.
Open IEF (100%) in the portfolio builder →Used in portfolios: All Weather, Ivy Portfolio, Larry Portfolio
Used in strategies: Global Tactical Asset Allocation (Aggressive), Adaptive Asset Allocation
Used in guides: All Weather, Ivy Portfolio, Larry Portfolio
Frequently asked questions
- How far back does IEF data go?
- IEF (Intermediate Treasuries (7-10y)) has its own monthly data from Aug 2002. Spliced with VFITX and FGOVX it reaches back to Feb 1985, which adds 17.5 years (42% of the extended history comes from proxies). Data through Sep 2026.
- What did IEF do before 2002?
- Before Aug 2002 the series is VFITX and FGOVX's. Those 17.5 years (Feb 1985–Jul 2002) show 8.7% a year with 5.0% annualized volatility and a worst drawdown of -9.3% (Oct 1993–Nov 1994). In major S&P 500 declines: 1987 crash, 1.7% versus -29.8% for the S&P 500 (FGOVX); 1998 LTCM sell-off, 3.4% versus -15.3% for the S&P 500 (VFITX); 2000–02 dot-com bear, 31.3% versus -44.7% for the S&P 500 (partly VFITX). The full extended history's worst drawdown is -23.2% (Jul 2020–Oct 2023).
- How closely does VFITX track IEF?
- Over 290 overlapping months (Aug 2002–Sep 2026), VFITX had a correlation of 0.982 with IEF, a tracking error of 2.2% a year and a tracking difference of -0.28% a year (grade: close). Over 290 overlapping months (Aug 2002–Sep 2026), FGOVX had a correlation of 0.961 with IEF, a tracking error of 2.8% a year and a tracking difference of -0.79% a year (grade: close).
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 IEF) times the square root of 12.
- Tracking difference
- Annualized geometric return of the proxy minus that of IEF over the overlap. Positive means the proxy earned more.
- Beta and vol ratio
- Beta is the covariance of the proxy with IEF divided by the variance of IEF; vol ratio is the proxy's standard deviation divided by IEF'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:
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Historical simulation, not investment advice. Past returns, including spliced proxy returns, do not predict future results.