The basis reflects the relationship between cash price and futures
price. (In futures trading, the term "cash" refers to the underlying
product). The basis is obtained by subtracting the futures price from the cash
The basis can be a positive or negative number. A positive basis
is said to be "over" as the cash price is higher than the futures
price. A negative basis is said to be "under" as the cash price is
lower than the futures price....