Currency traders are switching up their playbooks as some of the most time-tested strategies are fizzling in the $5.1-trillion-a-day market. Momentum, carry and value bets have delivered lackluster returns in foreign exchange this year, prompting some money managers to shelve them in favor of event-driven and niche positions. Oppenheimer Funds Inc. has cut the holding time for some wagers to weeks instead of months, while money manager Standish is looking at dollar options that would profit from risks related to trade disagreements. The FX landscape has proven challenging in 2018 amid questions about global growth ... (full story)