Answer:
The return of the portfolio is -2.5%.
Explanation:
You invest your 10,000 and the 5,000 obtained in the short (total 15,000) into one-year bills with 5% rate. At the end of the year, you will have 15,000 * 1.05 = $15,750. Total gain is equal to $750.
In the other hand, the stock is valued at $25 at the beggining, so the shor of $5,000 is equal to 5,000/25 = 200 shares. You have a negative dividend of $1 each share (total of $200) and a lost of $4 each share (total of $800). Total lost is equal to $1,000.
Net return is equal to $750 - $1,000 = -$250. In percent, -250/10,000 = -0,025 = -2,5%.