well, my understanding is that basis is the differnce between the spot price and the future price for a particular underlying and since you are heding the instrument right across, you are locking in that spread or in other words to say you are locking the future price of that underlying and hence eliminating the risk of having to buy the same at a higher price in future.
For eg. if you are hedging a forward oil contract for 1 year at a price of $41 and if the current oil price is $40, then eseentially by hedging you have fixed that $1 of basis and eliminated the risk for delievery after one year….
Other example you can take is with regards to cash bonds and CDS spreads. theoritically or lets say in normal market conditions, if the cash bond is trading at a spread of 200bps and 5-yr CDS at 150bps, ideally what you have is a negative basis of 50bps. (CDS-Cash 150-200bps). now since CDS is a leading indicator atlease relative to the bond value for the credit health of a particluar issuer, you base your trade on the thesis that since CDS has already tightened, bond is trading cheap and will come in eventually and hence buy the bond and take advantage of the negative basis. the only risk to this thesis is that if CDS widens due to some reason then you are toast.. CDS/Bond are compared here because these are the two ways to taking a long/short exposure to a particular issuer.
thoughts/Q’s/Make sense????