An indicator of post-market sentiment and trading activity, calculated by measuring the after-hours price levels of stocks within the Nasdaq 100 and using the same methodology as that used to create the Nasdaq 100 during regular trading sessions. Because some stocks may not be trading in the after-hours session, their prices will remain at the daily close when calculating the Nasdaq 100 after-hours indicator. Taobiz explains Nasdaq-100 After Hours Indicator Indicators of after-hours activity can be hard to come by and decipher, but in recent years the sheer rise in volume has made evaluating after-hours trading easier. For investors looking to place trades in the after hours markets, it is still always advisable to use limit orders, as trading levels are often thin in specific stocks. Typical after-hours trading sessions run from 4pml 6:30pm Eastern Standard Time for the Nasdaq 100.