The investment seeks to track the performance of a market-weighted bond index with a long-term dollar-weighted average maturity. The fund invests by sampling the Index, meaning that it holds a range of Securities that, in the aggregate, approximates the full Index in terms of key risk factors and other characteristics and invests at least 80% of assets in bonds held in the Index. It maintains a dollar-weighted average maturity consistent with that of the Index, which generally ranges between 15 and 30 years.
Fund filings (PDF) »

Asset managers:
Kenneth Volpert (Started: Jan 31, 2005)
Gregory Davis (Started: Apr 24, 2008)

Advisor Company:
The Vanguard Group, Inc.
Fund family reports on Morningstar »

	1 year	3 years	5 years	10 years
Alpha*	-20.05	0.05	-2.34	-2.66
Beta*	3.48	1.00	2.60	2.34
Mean annual return	2.08	0.57	0.49	0.66
R-squared*	93.87	99.78	88.30	88.25
Standard deviation	16.44	11.80	10.16	9.42
Sharpe ratio	1.51	0.38	0.28	0.53
* Against standard index

Risk measurement details »

Security	Net Assets
US Treasury Bond 8%	4.84%
US Treasury Bond 3.5%	2.98%
US Treasury Bond 6.25%	2.92%
US Treasury Bond	2.53%
US Treasury Bond 4.75%	2.38%
US Treasury Bond 7.125%	2.15%
US Treasury Bond 6.375%	1.99%
US Treasury Bond 5.5%	1.93%
US Treasury Bond 8.125%	1.85%
US Treasury Bond 5.375%	1.83%

Holdings Performance »