Overnight FX option expiry now captures the U.S. Federal Reserve, UK and euro zone policy meeting announcements, so the gains in related implied volatility can offer some indication of the expected reaction in the major currency pairs. EUR/USD overnight expiry implied volatility doubled to the highest all year at 17.0 - the premium/break-even for vanilla straddle now $80-pips in either direction. . Rest of the implied volatility curve is firmly underpinned, but short-dated risk reversals have pared their long-standing downside strike premium, suggesting concerns about EUR/USD topside potential. GBP/USD overnight implied volatility trades 15.5 from 10.0 and EUR/GBP 14.0 from 9.5 - gains of around 50% in related straddle premium/break-even for both to $85-pips and 50 GBP pips respectively. One-month expiry implied volatility slips to new recent lows at 7.0 after big UK CPI beat lifts Dec BoE hike probability and underpins GBP, but GBP put (downside srike) risk reversal premiums remain elevated. AUD/USD overnight implied volatility added around 33% to implied volatility (now 18.5) and related premium - $55-pips break-even in either direction for a straddle. Overnight expiry FX option implied volatility captures the key CB announcements Overnight expiry FX option implied volatility captures the key CB announcements For more click on FXBUZ Richard Pace is a Reuters market analyst. The views expressed are his own Editing by Mark Potter Our Standards: The Thomson Reuters Trust Principles.