The iShares Barclays TIPS Bond (NYSEArca:TIP) was the eighth-biggest U.S. ETF at the end of October, with $20.74 billion in assets, according to data compiled by IndexUniverse.com. The value of the bond's principal or the interest income paid is adjusted to track changes in an official inflation measure. Interest in inflation-protected bonds has been on the upswing amid growing concern among investors that all the monetary stimulus from central banks such as the Federal Reserve is creating inflationary pressure that will rear its head before long.