Is there any ETF, fund, security that closely tracks 30 year mortgage rates in the USA?
TBF - Proshares short 20+ Year Treasury The TBF fund is designed to track (hopefully) 100 percent of the inverse daily returns of the Barclays Capital 20+ Year U.S. Treasury Index.
there's some risk of tracking error, and also a compounding effect if it's down several days in a row. (invest with care)
There's also a TBT fund, but the risks are even greater since it is leveraged, potentially you could make the right long term call, but lose a lot in the short term due to tracking error and effect of compounding) (that would tend to make this one more appropriate for short term 'bets' on interest rates, and less so for a long term investor)
There are also quite a few floating rate closed-end funds (Click here, then click on "loan participation funds") that should do well in a rising rate environment. Just beware that these funds seem to incorporate a substantial amount of credit risk as well as floating interest rate exposure.
Closed end funds trade a lot like securities, since the fund is closed, you have to buy shares from another owner that is selling (just like with stocks), that means the shares can sometimes trade above or below the underlying value of the actual assets held by the fund depending on buying/selling pressure and the relative liquidity of a given fund.