RT Journal Article SR Electronic T1 Time-Varying Risk and Return in Global Portfolio Management JF The Journal of Investing FD Institutional Investor Journals SP 62 OP 69 DO 10.3905/joi.1999.319430 VO 8 IS 4 A1 Andreas C. Christofi A1 Panayiotis Theodossiou A1 Andreas Pericli YR 1999 UL https://pm-research.com/content/8/4/62.abstract AB This article examines the usefulness of an active portfolio strategy that uses time-varying parameters produced by a GARCH methodology. The results suggest that such a strategy outperforms alternative buy-and-hold strategies. When transaction costs are extended to include the bid-ask spread, investors can profit from adding low-cost levered positions, such as futures indexes, to their portfolios of equities.