The answer is in inflation expectation. Bond yields and inflation are intertwined. As we know, inflation eats the future returns of investments, so when people expect more inflation, bond yields tend to rise alongside them. Inflation also reduced the future stream of payments. For example, 1 dollar of profit today, would be valued at 0,5 dollar tomorrow with 100% inflation. This means that businesses's valuation that are heavily reliant on future returns tends to decline, since future profits are valued less than present ones. Those companies are typically technology firms, like Palantir, which recieve a lot of hype, without current profits, or revenues, but are highly thought to return big profits in the future.
See: https://www.investopedia.com/articles/bonds/09/bond-market-interest-rates.asp for bond yields and inflation.