Suppose the stock price is given by a Brownian motion W(t), i.e., S(t) = W(t), and the bond price B(t) is constant (B(t) 1). What kind of portfolios are self-financing? Give two total different portfolios (two portfolios are the same if the ratio is constant). Verify your answers.

[5] Suppose the stock price is given by a Brownian motion W(t), i.e., S(t) = W(t), and the bond price B(t) is constant (B(t) = 1). What kind of portfolios are self-financing? Give two total different portfolios (two portfolios are the same if the ratio is constant). Verify your answers. [5] Suppose the stock price is given by a Brownian motion W(t), i.e., S(t) = W(t), and the bond price B(t) is constant (B(t) = 1). What kind of portfolios are self-financing? Give two total different portfolios (two portfolios are the same if the ratio is constant). Verify your answers