Tesla Stock Downgraded to Sell By Someone I've Never Heard Of (TSLA)

Not that there's anything wrong with that.
Or is it "of whom I've never heard?"
The stock is down a buck at $304.20 after hitting $301.00. The $300 line is holding but being tested:

Finviz

From MarketWatch:

Tesla Inc. shares TSLA, -0.32% were downgraded to sell from hold by analyst Eric Ross at Cascend on Tuesday, who said his measurement of customer demand is beginning to flag. New customers who have not already preordered can't get new vehicles until 2019, he said, and are beginning to go elsewhere. "Additionally, all the known issues of capital burn/raises, Model 3 production issues, and increased competition," Ross wrote in a note....MORE

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The Short Argument Against Tesla
$300 Looks Like an Important Line For Tesla's Stock (TSLA)

It's not that $300 is some magical round number, rather looking at the chart if the stock moves decisively through that line there is a lot of air down to the $240 base where the run began.