How we extend ETF history before inception
The Drawdown Analyzer shows 40+ years of history for tickers whose ETF wrappers only launched in the 1990s or 2000s. Here's exactly how, and where to push back.
The problem
TLT launched in 2002. GLD launched in 2004. QQQ launched in 1999. If you measure their drawdowns only from their ETF inception, you miss the 1973-74 crash (SPY's worst bear market), the 1980-82 bond disaster (TLT's worst-ever period), and the entire history of gold before its secular bull run. A 2008-only view of risk is misleading because 2008 isn't the worst any of these asset classes ever did.
To give honest drawdown numbers, we need the underlying asset-class return series, not the ETF ticker's price history. The asset classes existed long before the ETFs that track them today.
The solution: proxy chain
For every ETF, we define an ordered fallback chain. We take the real ETF's adjusted-close series where it exists, then splice in the pre-inception history from the closest-tracked predecessor, usually an institutional index mutual fund that held the same assets under the same mandate. Returns, not levels, are what we stitch; the level series starts at the ETF's actual inception price and backs into the predecessor's returns for earlier dates.
Source: backend/app/backtest/fallback_table.py. Every backtest and drawdown run records its per-ticker chain in the build log, so you can always see which source tickers contributed to any period.
Per-ticker chains
Before 1985 the chain is broad large-cap growth, not Nasdaq-pure, with less tech concentration than QQQ.
TIPS were first issued in 1997, so nothing before 1998 is a traded TIPS price. That tail is a monthly series synthesized for research, densified to daily, and the build log names it whenever it serves. A scaled nominal-Treasury proxy (VFITX at 0.85) sits below it in the chain and only fires if the series is unavailable.
PCRIX (PIMCO CommoditiesPlus) used to cover 2002 to 2006, but its total-return reconciliation was inconclusive across data feeds, so ^SPGSCI covers that window too (under 3pp cumulative divergence). The pre-2002 leg moved from ^BCOM to ^SPGSCI in March 2026 after yfinance stopped returning reliable ^BCOM data.
No investable emerging-markets index existed before 1988, so the tail before 1988 is a research reconstruction, not a traded history. From 1988 the series is the MSCI Emerging Markets index. Until October 2026 an actively managed fund (Fidelity Emerging Markets, FEMKX) covered 1990 to 1994; the index covers those years now.
Why you can trust this
- Real institutional data. VFINX, VUSTX, VFITX, PIGIX, VEIEX etc. are index mutual funds with decades of audited NAV history. They are not synthetic. Two chains do end in reconstructions, TIPS before 1998 and emerging markets before 1988, and the chain says so where it happens.
- Same mandate. VFINX tracked the S&P 500 via full replication, the same exposure SPY does today. VUSTX tracked long Treasuries. The asset-class return series is the return series, wrapper aside. A fund tier counts only while its history is total return: VFINX's provider history lacks its 1976-1986 payouts, so those years use the S&P 500's own daily total return instead.
- Transparent. Every drawdown result carries its proxy chain in the build log. If a result seems off, you can verify which source data generated it.
- We disclose scaling. A couple of chains (VWO pre-2001, TIP pre-2000) apply a small volatility scaler to account for the emerging-markets vs developed-markets cap distribution, or nominal vs inflation-protected Treasuries. The scaler is in the fallback table and in the build log.
Known caveats
- Pre-ETF returns carry the predecessor fund's expense ratio, not the modern ETF's. For VFINX → SPY that's ~16bps vs ~9bps, small but nonzero.
- Intraday volatility is not comparable before ETFs existed. Mutual funds priced once per day; our series is daily only.
- Gold before 1975 was not freely tradable for US investors. We still show the series because the asset existed and its price history is well-documented, but treat pre-1975 drawdowns as reference context, not backtestable trades.
- The chain is ETF-level, not strategy-level. If a strategy uses a leveraged ETF (e.g. TQQQ, SSO), we synthesize leverage from the underlying index return minus a financing cost, see the backtest engine docs for that path.
See it in action
Run the drawdown analyzer on any portfolio and you'll get history back to 1968-1986 depending on which tickers you use.
Open Drawdown Analyzer