Vanguard is moving assets in some target funds out of longer-dated TIPS and into the Vanguard Short-Term Inflation-Protected Securities Index ( VTIPX ), and the ETF version is Vanguard Asset Allocation Fund ( VTIP ). VTIP's average duration is 2.5 years, versus a whopping 8.5 years for the traditional TIPS fund. Federal Reserve chairman Ben Bernanke hinted Wednesday the Fed may start unwinding its extraordinary bond-buying program later this year, causing stock and bond prices to plunge.