If the debt ceiling is not raised before the US government runs out of money (sometime over the summer), it could cause a bond market crisis, reducing investor confidence in US markets.
"the US government hit its debt sealing in January this year and US politicians are in the process of passing a quote big beautiful bill that includes a provision to raise the debt cealing if this spending bll does not get passed before the US government runs out of money it could risk causing a bond market crisis and this would reduce investor confidence in US markets and it would be a huge blow to that critical element that large foreign investors look for safe and liquid Bond markets"