Pragmatic-world nominal riskless rates are non-negative. However, conventional arbitrage theory has yet to develop a theoretical justification of this phenomenon. – We define the null-alternative cash as an investor holding onto cash and refraining from investment and consumption ("doing...

Private investors have limited time available for learning about stocks as they need to divide their time between stock analysis and work. This paper analyzes the influence of learning constraintsin the form of time constraints on portfolio selection and derives both optimal portfolio holdings...