$NVIDIA (NVDA.US)$ why I still cannot buy

Thanks to recent increases I have a chance to cash in on some oil stocks. My positions are $Chevron (CVX.US)$ , $Exxon Mobil (XOM.US)$ , $Camber Energy (CEI.US)$ , $Occidental Petroleum (OXY.US)$ and $Powershares Db Multi-Sector Commodi Powershares Db Oil Fund (DBO.US)$ . How long should I wait? I don't want to miss the potential for more returns, but I also realize that if I wait to long I can miss out all together. $S&P 500 Index (.SPX.US)$ $SPDR S&P 500 ETF (SPY.US)$ $Dow Jones Industrial Average (.DJI.US)$ $Nasdaq Composite Index (.IXIC.US)$
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$Camber Energy (CEI.US)$down down and more down please

$CapLand IntCom T (C38U.SG)$ to the moon! 🚀

$Microsoft (MSFT.US)$ going up