Matt founded and led Chimera since 2007.
Under his leadership, Chimera grew to a $3.8 billion mortgage REIT and paid more than $5.2 billion in dividends to shareholders.
Chimera's book value improved nearly 4% in the fourth quarter and over 16% at the middle of the year.
This improved book value, combined with the company's dividend policy, has generated a 6% economic return for the fourth quarter and a 22% economic return since June 30, 2020.
The National Association of Realtors recently reported that in December, contract closing for existing homes increased with annualized pace of 6.76 million units.
This is the strongest pace we have seen since late 2006.
At year-end, our GAAP investment portfolio included $12.6 billion of mortgage loans and $2.5 billion of non-agency RMBS.
Over 90% of the loans in non-agency securities on our balance sheet were originated prior to 2010.
In total, Chimera sponsored $4.2 billion and 11 separate securitized deals for the calendar year 2020, and we retained $655 million in subordinate notes.
Securitization is Chimera's primary source of financing for our loan portfolio, and as of year-end, securitized debt represented more than 60% of Chimera's liabilities.
At year-end, we have $3.2 billion of credit-related secured financings, which is 37% less than we were financing at the year-end 2019.
The average maturity of our credit-related financing is 15 months and $2 billion, or roughly two-thirds are either nonmark-to-market or limited mark-to-market.
During the fourth quarter of 2020, we exercised a capped call option, and the company elected to receive a settlement of approximately 4.7 million shares for our common stock, which were then retired.
Last night, our board of directors increased the size of our outstanding common stock repurchase authorization to 250 million.
In October, we issued CIM 2020-R6, with $418 million of reperforming loans purchased in September.
The underlying loan from the deal had a weighted average coupon of 5.25% and a weighted average loan age of 164 months.
The average loan size in the R6 transaction was $102,000 and had an average LTV of 71%.
The average FICO score of the borrower was 638.
We sold 334 million senior securities from the deal and retained 84 million in subordinate notes, plus interest-only securities.
Our cost of debt for the CIM 2020-R6 was 2.19%, with an 80% advance rate.
The R7 deal consisted of $653 million reperforming loans from the called CIM 2017-8 securitization.
The underlying loans in the deal had a weighted average coupon of 6.38% and a weighted average loan age of 172 months.
The average loan size in the R7 transaction was $81,000 and had an average LTV of 60%.
The average FICO score of the borrowers was 662.
We sold $552 million senior securities from the deal and retained $91 million in subordinated notes, plus interest-only securities.
Our cost of debt for the R7 deal was 2.22%, with an 86% advance rate.
The collateral for the NR1 securitization was $132 million of non-performing loans called from CIM 2017-8 deal.
The underlying loans had a weighted average coupon of 5.76% and a weighted average loan age of 170 months.
The average loan size was $100,000, had an 86 LTV and a 589 average FICO.
We sold $84 million notes, with a 4.49% cost of debt and a 64% advance rate.
Chimera retained $48 million of subordinate notes.
The deal was rated by Moody's, Fitch and DBRS and had $327 million loans, with a weighted average coupon of 3.09% and a weighted average loan age of two months.
The average loan size was $912,000 and at an average FICO of 782 and an average LTV of 64%.
As of year-end, Chimera owns call rights from 7 billion in 16 previously issued same deals that are either currently callable or will become callable in 2021.
GAAP book value at the end of the fourth quarter was $12.36 per share, and our economic return on GAAP book value was 6% based on the quarterly change in book value and the fourth-quarter dividend per common share.
GAAP net income for the fourth quarter was $129 million or $0.49 per share and $15 million or $0.07 for the full year.
On a core basis, net income for the fourth quarter was $72 million or $0.29 per share, and it was $334 million or $1.46 per share for the full year.
Economic net interest income for the fourth quarter was $117 million, and it was $513 million for the full year.
For the fourth quarter, the yield on average interest earning assets was 5.9%, our average cost of funds was 3.6% and our net interest spread was 2.3%.
Total leverage for the fourth quarter was 3.6 to 1, while recourse leverage ended the quarter at 1.2 to 1.
For the fourth quarter, our economic net interest return on equity was 12.5%, and our GAAP return on average equity was 15.8%.
Expenses for the fourth quarter, excluding servicing fees and transaction expenses, were $18 million, up slightly from last quarter.

Summary:
Last night, our board of directors increased the size of our outstanding common stock repurchase authorization to 250 million.
GAAP net income for the fourth quarter was $129 million or $0.49 per share and $15 million or $0.07 for the full year.
On a core basis, net income for the fourth quarter was $72 million or $0.29 per share, and it was $334 million or $1.46 per share for the full year.