Tesla is currently in Junk status (that is, below BBB- rating). But within Junk status, there are degrees. Tesla's current rating is Caa1, well below Baa3, according to a rating in March 2018 earlier this year.
FYI: That puts Tesla's bonds as 6-steps BELOW "junk" status. Tesla is well into junk status and is considered a highly speculative bond.
If Tesla's financials continue to degenerate (and remember: this is a company that was losing 300-million per quarter BEFORE the Model3 ramp-up. Who knows how much "the tent" and all of those extra workers cost??), then Moody's will be forced to lower Tesla's bond rating even lower.
"Default Imminent" is a rating of Caa3. Tesla is literally 2-steps away from "Default imminent". Below Caa3 are the ratings of Ca, and C, when the company is finally entering default officially.
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Remember that Tesla has bonds coming due at the end of 2018 and the beginning of 2019. Tesla needs to pay off those bonds somehow, and so far... it seems unlikely that they can pay it off using profits.
Maybe Tesla will reach profitability in the next few months, but their runway is definitely running out.