When I read up on swap spreads, the definition always goes something like this: The swap spread is the difference between the fixed leg of swap and a Treasury bond with the same maturity.
So if the fixed leg of a 10y swap is 8% and the Treasury bond has a rate of 5%, the spread is 3%. What confuses me about this is that I thought the fixed rate of the swap depends on the floating leg: If a company has a variable interest rate of Libor + 2%, they will probably get a different fixed rate in a swap compared to a company with Libor + 1%. And that would lead to a different swap spread.
Could someone point out where my mistake is?