"i wanted to buy TBF and TBT for shorting government bonds, but my bank advised that they think these are not suitable for "buy and hold" because of the costs of rolling the instruments. i do not quite understand to what they are referring. I would be most grateful if you can advise whether or not you think the cost is a valid point. as always thatnks for the wonderful service."

David Fuller's view Thanks for your kind words. I agree with your bank and have written that the ProShares funds are for short to medium-term trading, on a buy-low-sell-high basis, rather than for long-term holding. My point was that if you short a bond, you are paying rather than receiving the coupon interest rate. This is reflected in the rollover costs of the futures contracts that the ProShares funds would be shorting.