# Future spot price versus current forward price

Which are the two conditions necessary to claim that the future spot price will have as many chances to be above or below the current forward price?

• Is this a homework assignment? – olaker Jun 27 '14 at 9:56

Using the $T$-forward measure $Q^T$, where the numeraire is the price of the zero-coupon bond $p(t, T)$ maturing at time $T$, we can see that the forward rate is the expectation of the future short rate $r_T$:
$$f(t,T) = \mathbb{E}^T \left[ r_T \mid \mathcal{F}_t \right] \, .$$