English

Cost-efficiency in Incomplete Markets

Portfolio Management 2026-05-13 v3 Probability Mathematical Finance

Abstract

This paper studies the topic of cost-efficiency in incomplete markets. A payoff is called cost-efficient if it achieves a given probability distribution at some given investment horizon with a minimum initial budget. Extensive literature exists for the case of a complete financial market. We show how the problem can be extended to incomplete markets and how the main results from the theory of complete markets still hold in adapted form. In particular, we find that in incomplete markets, the optimal portfolio choice for non-decreasing preferences that are diversification-loving (a notion introduced in this paper) must be "perfectly" cost-efficient. This notion of perfect cost-efficiency is shown to be equivalent to the fact that the payoff can be rationalized, i.e., it is the solution to an expected utility problem.

Keywords

Cite

@article{arxiv.2206.12511,
  title  = {Cost-efficiency in Incomplete Markets},
  author = {Carole Bernard and Stephan Sturm},
  journal= {arXiv preprint arXiv:2206.12511},
  year   = {2026}
}

Comments

32 pages. Examples and Counterexamples have been relegated to a separate document, upon journal editor's request: arXiv:2407.08756

R2 v1 2026-06-24T12:03:35.171Z