So if an eft has a current price above it's nav price after hours, is the stock more likely to drop when the market opens again

If an ETF has a current price above its NAV price after hours, it does not necessarily indicate a higher likelihood of the stock dropping when the market opens again. However, it does suggest that there may be a premium in the market for the ETF at that moment.

1. Arbitrage Mechanisms: The price of an ETF typically stays close to its NAV during the day, as arbitrage activity helps align the market price with the underlying value. This means that if the ETF's price deviates significantly from its NAV, there is an opportunity for arbitrageurs to profit by buying and selling the ETF and its underlying securities. This activity can quickly bring the price back in line with the NAV.
2. Market Volatility and Liquidity: The extent to which the ETF's price reverts to its NAV after hours depends on market conditions and liquidity. If the market is volatile or illiquid, the price may not immediately adjust to the NAV, especially if there are restrictions on the underlying securities that affect the ETF's creation and redemption process.
3. Investor Sentiment: The price of an ETF can also reflect changes in market sentiment, which may not be fully captured in the NAV. For example, if there is a significant news event that affects the underlying securities, the market price may reflect this before the NAV is updated.
4. Day-Ahead NAV: It's important to note that the NAV used to calculate the premium or discount is typically a day-ahead NAV, which may not fully reflect the current market conditions. As new information becomes available and the markets open, the NAV may be updated, which could affect the premium or discount.

In conclusion, while a premium indicates a discrepancy between the ETF's market price and its NAV, it does not automatically imply that the price will drop when the market opens. Arbitrage activity, market conditions, and investor sentiment can all influence the price movements of an ETF. Investors should monitor the ETF's price and news surrounding the underlying securities to make informed decisions.