Global Financial Crises and Time‐Varying Volatility Comovement in World Equity Markets

This paper studies volatility comovement in world equity markets between 1994 and 2008. Global volatility factors are extracted from a panel of monthly volatility proxies relating to 25 developed and 20 emerging stock markets. A dynamic factor model (FM) is estimated using two‐year rolling‐window regressions. The FM's time‐varying variance shares of global factors map variations in volatility comovement over time and across countries. The results indicate that global volatility linkages are significantly stronger during financial crisis periods in Asia (1997‐1998), Brazil (1999), Russia (1998) and the United States (2000, 2007‐2008). Emerging markets are weakly synchronised with world volatility in comparison with developed markets. In particular, emerging market comovement is significantly lower than developed market comovement during the Asian and US sub‐prime crises. This suggests a degree of decoupling of emerging markets from the global drivers of volatility during these periods.     

Coopetition-based business models: The case of Amazon.com

Coopetition (collaboration between competing firms) is a phenomenon that has recently captured a great deal of attention due to its increasing relevance to business practice. However, current research on coopetition is still short on explaining how the potential advantages of coopetition can be realized over time as part of an individual firm's business model. In order to gain insights into this, we conduct a longitudinal, in-depth case study on the coopetition-based business models of Amazon.com. We find evidence of three distinct coopetition-based business models: (1) Amazon Marketplace, (2) Amazon Services and Web Services, and (3) the collaboration between Apple and Amazon on digital text platforms. We conclude by forwarding several propositions on how value can be created and captured by involving competitors in a firm's business model. As a whole, the results contribute to the current understanding of how firms – as well as their stakeholders – can better benefit from coopetition.     

Healthcare resource utilization among patients with relapsed multiple myeloma in the UK,France, and Italy

Aims: To assess the real-world healthcare resource utilization (HRU) and costs associated with different treatment regimens used in the management of patients with relapsed multiple myeloma in the UK, France, and Italy.

Methods: Retrospective medical chart review of characteristics, time to progression, level of response, HRU during treatment, and adverse events (AEs). Data collection started on June 1, 2015 and was completed on July 15, 2015. In the 3 months before record abstraction, eligible patients had either disease progression after receiving one of their country’s most commonly prescribed regimens or had received the best supportive care and died. Costs were calculated based on HRU and country-specific diagnosis-related group and/or unit reference costs, amongst other standard resources.

Results: Physicians provided data for 1,282 patients (387 in the UK, 502 in France, 393 in Italy) who met the inclusion criteria. Mean [median] total healthcare costs associated with a single line of treatment were €51,717 [35,951] in the UK, €37,009 [32,538] for France, and €34,496 [42,342] for Italy, driven largely by anti-myeloma medications costs (contributing 95.0%, 90.0%, and 94.2% of total cost, respectively). During active treatment, the highest costs were associated with lenalidomide- and pomalidomide-based regimens. Mean cost per month was lowest for patients achieving a very good partial response or better. Unscheduled events (i.e. not considered part of routine management, whether or not related to multiple myeloma, such as unscheduled hospitalization, AEs, fractures) accounted for 1–9% of total costs and were highest for bendamustine.

Limitations: The use of retrospective data means that clinical practice (e.g. use of medical procedures, evaluation of treatment response) is not standardized across participating countries/centers, and some data (e.g. low-grade AEs) may be incomplete or differently adjudicated/reported. The centers involved may not be fully representative of national practice.

Conclusions: Drug costs are the main contributor to total HRU costs associated with multiple myeloma. The duration of active treatment may influence the average total costs, as well as response, associated with a single line of therapy. Improved treatment outcomes, and reductions in unscheduled events and concomitant medication use may, therefore, reduce the overall HRU and related costs of care in multiple myeloma.     

Correction to: Inside Buchanan’s Samaritan’s Dilemma: altruism,strategic courage and ethics of responsibility

Economics of Governance - The Samaritan’s Dilemma has largely been investigated, frequently by assuming that Samaritans help recipients out of altruism. Yet, Buchanan did not make any...     

Dynamic mean–variance problem with frictions

Finance and Stochastics - We study a dynamic mean–variance portfolio selection problem with return predictability and trading frictions from price impact. Applying mean-field type control...