As CEO of Dynex, I'm very proud to report that in 2020 we delivered a 15.2% total economic return and a 17% total shareholder return.
I've been at Dynex for 13 years and no other year has demanded as much active decision making as 2020.
And when you look at our long-term chart on Page 17, you can see that we have delivered solid returns through multiple market cycles during my tenure at Dynex Capital.
So in the past 12 months we have taken a strategic view on both sides of the balance sheet with the goal of being able to grow and scale the Company efficiently, and in a stakeholder-friendly manner.
We retired two of our higher cost preferred stock issues and we replaced them with our new Dynex Capital Preferred C. And during the last two weeks, we issued approximately $56 million in common equity in line with our long-term strategy to grow our capital base.
We've been in business for 30 years and we are fully committed to delivering solid cash flow, and attractive total returns to our shareholders well into the future.
For the quarter on a per common share basis we recorded comprehensive income of $1.23, total economic return of $1.22 or 6.7% based on the beginning book value per share of $18.25 and core net operating income of $0.45.
For the year on a per common share basis, we reported comprehensive income of $2.88, total economic return of $2.73 and core net operating income of $1.94.
Realized and unrealized investment in TBA gains, net of hedges, were approximately $1.83 per common share, driving a large part of the comprehensive income and total economic return for the year.
Core net operating income sequentially declined from $0.61 last quarter to $0.45 this quarter, principally as a result of the smaller average balance of interest-earning assets and modestly declining asset yields.
In addition, general and administrative expenses increased $2.1 million during the fourth quarter from year end incentive compensation accruals reflecting a catch-up adjustment for accrued bonus expense for management's achievements of its corporate goals and objectives this year.
Net interest spread and adjusted net interest spread, both slightly declined by 2 basis points respectively quarter-over-quarter.
Agency RMBS prepayment speeds were 17.1 CPR for the quarter.
While overall portfolio CPRs including the CMBS portfolio were approximately 15.1 CPR.
As it relates to book value, the driver of the $0.83 per share increase during the fourth quarter was net gains from continued spread tightening on investment assets, particularly in both lower coupon TBAs and pools.
We estimate that book value per common share at the end of January is up approximately 1%, inclusive of the impact of the capital raise announced last week.
We ended the year with investment assets, including TBA securities of $4.2 billion and leverage at 6.3 times shareholders equity similar to the end of the third quarter.
Overall investment assets, including TBA securities were down on an average basis by approximately 7% as compared to last quarter.
This quarter we added 15-year agency RMBS investments through TBA positions and overall the portfolio composition is approximately 84% RMBS investments, including TBA securities and approximately 16% invested in CMBS and CMBS IO.
For 2020, dividends in both the preferred stock and common stock were a 100% capital gain income.
Our annual total economic return of 15% is only the third best in Dynex's history since 2008, but it is remarkable in that it was earned in an outlier year like 2020.
The Fed also remains committed to a broad recovery in employment, and an overshoot of inflation over 2%.
We expect returns to move into the 10% to 12% range and could offer mid-teens returns if spreads widen.
Book value since year-end is up about 1% net of the equity rate.
We have a strong liquidity position of $375 million and tremendous upside earnings power on the balance sheet.
Leverage stands slightly over 6 times today and we still believe a liquid strategy is appropriate for the environment.
We currently have an RMBS portfolio allocation of 20% to 15 years, which outperform in a steepener relative to 30s [Phonetic].
You can see on Page 10 of the slide deck that the portfolio performs relatively well across several types of rate shocks, both parallel and non-parallel.
A one times increase in leverage, invested at 8% total economic return, adds $0.19 per share per year in economic return.
At 10%, that's $0.24, at 12% it's $0.29.
We think we have the room to take our total leverage up at least 2 times from today's levels at the right time and possibly higher if the return environment is better.
We've used the Russell 2000 value index and the shift is mainly because of the unusual attraction and performance returns of this tech sector.

Summary:
For the quarter on a per common share basis we recorded comprehensive income of $1.23, total economic return of $1.22 or 6.7% based on the beginning book value per share of $18.25 and core net operating income of $0.45.
Core net operating income sequentially declined from $0.61 last quarter to $0.45 this quarter, principally as a result of the smaller average balance of interest-earning assets and modestly declining asset yields.