TLT's AH gap often rivals it's day returns. More over, the gap is often negatively correlated with returns during normal trading hours. This presents as the daily zigzag observed between daily returns (Blue) and AfterHours returns (Red). A 5 day EMA (bottom) of both AH and intraday returns shows when its most profitable to be long/short TLT by day and then take the opposite position (short/long) by night.