What did AGG do before 2003?

Before Oct 2003 the series is VBMFX's. Those 16.8 years (Jan 1987–Sep 2003) show 7.8% a year with 4.2% annualized volatility and a worst drawdown of -5.8% (Feb 1987–Sep 1987). In major S&P 500 declines: 1987 crash, 1.9% versus -29.8% for the S&P 500 (VBMFX); 1998 LTCM sell-off, 2.1% versus -15.3% for the S&P 500 (VBMFX); 2000–02 dot-com bear, 21.3% versus -44.7% for the S&P 500 (VBMFX). The full extended history's worst drawdown is -17.1% (Jul 2020–Oct 2022).

How closely does VBMFX track AGG?

Over 276 overlapping months (Oct 2003–Sep 2026), VBMFX had a correlation of 0.978 with AGG, a tracking error of 0.9% a year and a tracking difference of -0.03% a year (grade: close).

How far back can you test AGG? To Jan 1987, with VBMFX

Computed by the MarketHeist portfolio engine · Published 2026-10-10 · Updated 2026-10-10 · Data through Sep 2026

AGG (US Aggregate Bond) has its own monthly data from Oct 2003. Spliced with VBMFX it reaches back to Jan 1987, which adds 16.8 years (42% of the extended history comes from proxies). Data through Sep 2026.

What you'd have missed

AGG's own data starts in Oct 2003; VBMFX extends it to Jan 1987, 16.8 more years.
Its own history misses the 1987 crash, the 1998 LTCM sell-off and the 2000–02 dot-com bear.
Its worst drawdown, -17.1% (Jul 2020–Oct 2022), is already inside the ETF's own history; the extension does not change the worst case.
BND is extended with the same VBMFX.

How the history is built

AGG (ETF) Oct 2003 → now

VBMFX (Vanguard Total Bond Market Index Fund, mutual fund) used Jan 1987 → Sep 2003; its own data runs Jan 1987 → now

Jan 1987Sep 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 AGG

Proxy	Kind	Months contributed	Overlap with AGG	Correlation	Tracking error	Tracking difference	Beta	Vol ratio	Grade
VBMFXVanguard Total Bond Market Index Fund	mutual fund	Jan 1987–Sep 2003201 months	Oct 2003–Sep 2026276 months	0.978	0.94%	-0.03%	0.93	0.95	Close

Statistics are over the months a proxy and AGG 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.

AGG's own history versus the extended history

	The ETF's own history	Proxy years only	Full extended history
Window	Oct 2003 – Sep 202623.0 years	Jan 1987 – Sep 200316.8 years	Jan 1987 – Sep 202639.8 years
Growth of $10,000	$19,227	$35,100	$67,487
CAGR	2.9%	7.8%	4.9%
Annualized volatility	4.5%	4.2%	4.4%
Sharpe ratio (risk-free 0%)	0.66	1.81	1.12
Max drawdown	-17.1%Jul 2020 → Oct 2022; not yet recovered	-5.8%Feb 1987 → Sep 1987; recovered Jan 1988	-17.1%Jul 2020 → Oct 2022; not yet recovered
Worst complete calendar year	2022 (-13.0%)	1994 (-2.6%)	2022 (-13.0%)
Best complete calendar year	2019 (8.5%)	1995 (18.3%)	1995 (18.3%)
Longest underwater (months)	74	13	74
Major declines covered	3	3	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

Log scale, so the early decades are not flattened. Grey is the proxy period; blue is AGG's own data. Dashed lines mark where each fund's returns begin.

Drawdowns

Decline from the prior peak at month-end, the "underwater" curve.

How AGG did in each major US stock-market decline since 1985

Decline	S&P 500	AGG over the same months	Source of those months
1987 crashSep 1987–Nov 1987	-29.8%	1.9%	VBMFX
1998 LTCM sell-offJul 1998–Aug 1998	-15.3%	2.1%	VBMFX
2000–02 dot-com bearSep 2000–Sep 2002	-44.7%	21.3%	VBMFX
2007–09 financial crisisNov 2007–Feb 2009	-50.8%	6.5%	ETF
2020 COVID crashJan 2020–Mar 2020	-19.4%	3.1%	ETF
2022 inflation bearJan 2022–Sep 2022	-23.9%	-14.4%	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.

AGG's own five deepest drawdowns (extended history)

Peak	Trough	Depth	Recovery	Source of the decline months
Jul 2020	Oct 2022	-17.1%	not yet recovered	ETF
Feb 1987	Sep 1987	-5.8%	Jan 1988	VBMFX
Jan 1994	Jun 1994	-5.0%	Feb 1995	VBMFX
Apr 2008	Oct 2008	-4.3%	Dec 2008	ETF
Apr 2013	Aug 2013	-4.1%	May 2014	ETF

This covers declines the equity windows miss, such as the bond bear markets of 1994 and 2022.

Caveats

Before Oct 2003 the returns are VBMFX's, after that fund's own costs; the measured gap while both existed is -0.03% 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 VBMFX begins Jan 1987; the fund itself may be older.

Test it yourself

Open AGG as a one-asset portfolio in the live app, where every number recomputes from fresh data.

Open AGG (100%) in the portfolio builder →

Used in guides: 60/40 (SPY/AGG)

All fund histories →

Frequently asked questions

How far back does AGG data go?: AGG (US Aggregate Bond) has its own monthly data from Oct 2003. Spliced with VBMFX it reaches back to Jan 1987, which adds 16.8 years (42% of the extended history comes from proxies). Data through Sep 2026.
What did AGG do before 2003?: Before Oct 2003 the series is VBMFX's. Those 16.8 years (Jan 1987–Sep 2003) show 7.8% a year with 4.2% annualized volatility and a worst drawdown of -5.8% (Feb 1987–Sep 1987). In major S&P 500 declines: 1987 crash, 1.9% versus -29.8% for the S&P 500 (VBMFX); 1998 LTCM sell-off, 2.1% versus -15.3% for the S&P 500 (VBMFX); 2000–02 dot-com bear, 21.3% versus -44.7% for the S&P 500 (VBMFX). The full extended history's worst drawdown is -17.1% (Jul 2020–Oct 2022).
How closely does VBMFX track AGG?: Over 276 overlapping months (Oct 2003–Sep 2026), VBMFX had a correlation of 0.978 with AGG, a tracking error of 0.9% a year and a tracking difference of -0.03% 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 AGG) times the square root of 12.
Tracking difference: Annualized geometric return of the proxy minus that of AGG over the overlap. Positive means the proxy earned more.
Beta and vol ratio: Beta is the covariance of the proxy with AGG divided by the variance of AGG; vol ratio is the proxy's standard deviation divided by AGG'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: e6a5b5e30b36ff06

Historical simulation, not investment advice. Past returns, including spliced proxy returns, do not predict future results.