[dhc]

i looked it up on wiki but i don't understand what it says:

Freddie Mac/Fannie Mae's primary method of making money is by charging a guarantee fee on loans that it has purchased and securitized into mortgage-backed security bonds. Investors, or purchasers of Freddie Mac MBS, are willing to let Freddie Mac keep this fee in exchange for assuming the credit risk, that is, Freddie Mac's guarantee that the principal and interest on the underlying loan will be paid back regardless of whether the borrower actually repays.

thank you in advance

[WeStopForeclosureUSA]

they get paid by owning the mortgages that Wells, WAMU... are servicing. The interest paid on loans is profit so when they purchase a mortgage in the secondary market they are actually buying payments. Hope that helps.
PS when a servicer modifies a Fannie or Freddie loan they servicer actually loses some of the income, the basics there is more to know but do not want to bore you with details.