  We study markets with no riskless (safe) asset. We derive the corresponding
Black-Scholes-Merton option pricing equations for markets where there are only
risky assets which have the following price dynamics: (i) continuous
diffusions; (ii) jump-diffusions; (iii) diffusions with stochastic
volatilities, and; (iv) geometric fractional Brownian and Rosenblatt motions.
No arbitrage and market completeness conditions are derived in all four cases.
