> It just turns out tech was especially vulnerable.
This should not be surprising at all! The entire tech rally was fueled by a huge amount of leverage. That leverage was very cheap in the last 10 years, because there was a lot of money sloshing around and the interest rates were zero (sometimes even negative), which meant that the bar on portfolio returns was very low.
I'm going to simplify a lot: let's say you have a portfolio that returns 10% p.a., if the risk free rate (ie bond returns) are 0, then you can say that your portfolio gives people 10% in excess of what they could get by holding safe assets. But now rates are 5% (for the sake of simplicity), that same portfolio only gives you 5% excess returns. On any single given year that's not a huge difference, but if you compound this over 10 years, that's the difference of having earned 60% vs. 160%. Huge difference!
So as you can see this relatively small (in absolute terms) change really compounds itself into a massive re-evaluation of investments. When rates are negative, you'd be happy to hold assets that merely do nothing - ie neither gain nor lose value - but once rates start to rise appreciably, the future value of those investments needs to be discounted and because we are dealing with compounding, the discounting itself can be pretty brutal. This is then further compounded by the expectation that money supply itself is shrinking, which makes the pool of available money smaller as well.
It's really a double whammy which will mostly affect highly leveraged and risky bets, as they become much much less palatable.
It was really perverse how many tech companies had no discernible avenue of ever becoming profitable, and yet had billion dollar valuations. People were looking desperate for parking capital anywhere they could.