Bank account
= Bank account
In a discrete-time market, the bank account reinvests at each successive <spot interest rate>:
$$
B_0=1,
\qquad B_t=\prod_{s=0}^{t-1}(1+r_s).
$$
= Bank account
In a discrete-time market, the bank account reinvests at each successive <spot interest rate>:
$$
B_0=1,
\qquad B_t=\prod_{s=0}^{t-1}(1+r_s).
$$