Spread risk vs credit migration risk


Is spread risk same as credit migration risk?

I’m reading section 2.2 in reading 25 and I can’t really figure out whats the difference between the two…

Similar and related but different. Spread risk involves changed in the spreads, widening or narrowing. Zspread, oas or gspread for instance.

Credit risk involves a bond may default or other issues… usually high yield bonds.

recall the formula for XS = Sxt - (dS x SD) - (pxtxl)