Fannie Mae and Freddie Mac have prevented almost 2 million foreclosures since the enterprises were taken under federal conservatorship in 2008, according to a report by the Federal Housing Finance Agency (FHFA).

Nearly 1.7 million of the preventions -- including over 1 million actions in permanent loan modifications -- allowed borrowers to retain their homes, the FHFA said.

In the third quarter, Fannie and Freddie increased the number of foreclosure preventions to 140,258, up from 135,419 in the second quarter. The increase was led by 2,368 more loan modifications and 2,979 more repayment plans, compared to the previous quarter said the FHFA.

Two thirds of borrowers with loan modifications had monthly payments reduced by over 20 percent during the third quarter, it added.

During the third quarter, Fannie and Freddie also took over and disposed of fewer properties through short sales and deeds in lieu of foreclosure. The two agencies had 30,809 such actions, down from 32,210 in the second quarter.

Refinancings through the Home Affordable Refinance Program (HARP) increased 11 percent during the third quarter to nearly 928,600.

Serious delinquency rates, in which borrowers are 90 or more days behind on payments, declined to 3.81 percent from 3.85 percent in the third quarter. The percentage of loans that have missed one payment increased to 2.07 during the third quarter from 2.04 percent in the previous quarter.

Fannie and Freddie's delinquency rates are below the third quarter national average of 7.99 percent, according to the Mortgage Bankers Association. The two agencies guarantee around half of all U.S. mortgages.