What did TLT do before 2002?

Before Aug 2002 the series is VUSTX's. Those 16.2 years (Jun 1986–Jul 2002) show 8.9% a year with 8.1% annualized volatility and a worst drawdown of -12.2% (Feb 1987–Sep 1987). In major S&P 500 declines: 1987 crash, 2.4% versus -29.8% for the S&P 500 (VUSTX); 1998 LTCM sell-off, 4.3% versus -15.3% for the S&P 500 (VUSTX); 2000–02 dot-com bear, 31.0% versus -44.7% for the S&P 500 (partly VUSTX). The full extended history's worst drawdown is -47.6% (Jul 2020–Oct 2023).

How closely does VUSTX track TLT?

Over 290 overlapping months (Aug 2002–Sep 2026), VUSTX had a correlation of 0.992 with TLT, a tracking error of 2.3% a year and a tracking difference of +0.08% a year (grade: close).

How far back can you test TLT? To Jun 1986, with VUSTX

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

TLT (Long-Term Treasuries (20y+)) has its own monthly data from Aug 2002. Spliced with VUSTX it reaches back to Jun 1986, which adds 16.2 years (40% of the extended history comes from proxies). Data through Sep 2026.

What you'd have missed

TLT's own data starts in Aug 2002; VUSTX extends it to Jun 1986, 16.2 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, -47.6% (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

TLT (ETF) Aug 2002 → now

VUSTX (Vanguard Long-Term Treasury Fund, mutual fund) used Jun 1986 → Jul 2002; its own data runs Jun 1986 → now

Jun 1986Sep 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 TLT

Proxy	Kind	Months contributed	Overlap with TLT	Correlation	Tracking error	Tracking difference	Beta	Vol ratio	Grade
VUSTXVanguard Long-Term Treasury Fund	mutual fund	Jun 1986–Jul 2002194 months	Aug 2002–Sep 2026290 months	0.992	2.25%	+0.08%	0.88	0.89	Close

Statistics are over the months a proxy and TLT 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.

TLT'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	Jun 1986 – Jul 200216.2 years	Jun 1986 – Sep 202640.3 years
Growth of $10,000	$21,608	$39,802	$86,002
CAGR	3.2%	8.9%	5.5%
Annualized volatility	13.5%	8.1%	11.6%
Sharpe ratio (risk-free 0%)	0.30	1.10	0.52
Max drawdown	-47.6%Jul 2020 → Oct 2023; not yet recovered	-12.2%Feb 1987 → Sep 1987; recovered Feb 1988	-47.6%Jul 2020 → Oct 2023; not yet recovered
Worst complete calendar year	2022 (-31.2%)	1999 (-8.6%)	2022 (-31.2%)
Best complete calendar year	2011 (34.0%)	1995 (30.2%)	2011 (34.0%)
Longest underwater (months)	74	18	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

Log scale, so the early decades are not flattened. Grey is the proxy period; blue is TLT'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 TLT did in each major US stock-market decline since 1985

Decline	S&P 500	TLT over the same months	Source of those months
1987 crashSep 1987–Nov 1987	-29.8%	2.4%	VUSTX
1998 LTCM sell-offJul 1998–Aug 1998	-15.3%	4.3%	VUSTX
2000–02 dot-com bearSep 2000–Sep 2002	-44.7%	31.0%	partly VUSTX
2007–09 financial crisisNov 2007–Feb 2009	-50.8%	20.0%	ETF
2020 COVID crashJan 2020–Mar 2020	-19.4%	22.1%	ETF
2022 inflation bearJan 2022–Sep 2022	-23.9%	-29.9%	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.

TLT's own five deepest drawdowns (extended history)

Peak	Trough	Depth	Recovery	Source of the decline months
Jul 2020	Oct 2023	-47.6%	not yet recovered	ETF
Dec 2008	Dec 2009	-21.8%	Sep 2011	ETF
Jul 2012	Dec 2013	-18.2%	Nov 2014	ETF
Jul 2016	Oct 2018	-15.1%	May 2019	ETF
Jan 2015	Jun 2015	-14.2%	Jun 2016	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 VUSTX's, after that fund's own costs; the measured gap while both existed is +0.08% 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 VUSTX begins Jun 1986; the fund itself may be older.

Test it yourself

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

Open TLT (100%) in the portfolio builder →

Used in portfolios: Golden Butterfly, All Weather, Permanent Portfolio, Dragon Portfolio, Global Asset Allocation, Yale Endowment (Swensen)

Used in strategies: Risk Parity (inverse-vol), Adaptive Asset Allocation

Used in guides: All Weather, Dragon, Global Asset Allocation, Golden Butterfly, Permanent, Yale (Swensen)

All fund histories →

Frequently asked questions

How far back does TLT data go?: TLT (Long-Term Treasuries (20y+)) has its own monthly data from Aug 2002. Spliced with VUSTX it reaches back to Jun 1986, which adds 16.2 years (40% of the extended history comes from proxies). Data through Sep 2026.
What did TLT do before 2002?: Before Aug 2002 the series is VUSTX's. Those 16.2 years (Jun 1986–Jul 2002) show 8.9% a year with 8.1% annualized volatility and a worst drawdown of -12.2% (Feb 1987–Sep 1987). In major S&P 500 declines: 1987 crash, 2.4% versus -29.8% for the S&P 500 (VUSTX); 1998 LTCM sell-off, 4.3% versus -15.3% for the S&P 500 (VUSTX); 2000–02 dot-com bear, 31.0% versus -44.7% for the S&P 500 (partly VUSTX). The full extended history's worst drawdown is -47.6% (Jul 2020–Oct 2023).
How closely does VUSTX track TLT?: Over 290 overlapping months (Aug 2002–Sep 2026), VUSTX had a correlation of 0.992 with TLT, a tracking error of 2.3% a year and a tracking difference of +0.08% 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 TLT) times the square root of 12.
Tracking difference: Annualized geometric return of the proxy minus that of TLT over the overlap. Positive means the proxy earned more.
Beta and vol ratio: Beta is the covariance of the proxy with TLT divided by the variance of TLT; vol ratio is the proxy's standard deviation divided by TLT'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: 480030be1bee91c9

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