Oh wow, that's a change. But FWIW, I don't think it's very helpful to look at an aggregate like that, which doesn't distinguish between (at least pre-crisis) ratings. For some other datapoints, I would recommend:
1) S&P BB-rated bond index (just below investment grade), which shows a 6.3% yield for that grade.
1) S&P BB-rated bond index (just below investment grade), which shows a 6.3% yield for that grade.
https://fred.stlouisfed.org/series/BAMLH0A1HYBBEY
2) I do see a 10% yield at the B rating:
https://fred.stlouisfed.org/series/BAMLH0A2HYBEY
So that must be what the market is effectively classing Airbnb as.
3) The Vanguard high-yield corporate fund, which shows an 8.1% yield:
https://investor.vanguard.com/mutual-funds/profile/overview/...
(Also an aggregate like the high yield index you listed and noisy for that reason.)