In addition, our wholly-owned captive broker-dealer subsidiary, BES, became fully operational in the third quarter of 2016 as a member of the FICC, providing us with access to additional repo funding with favorable rates and haircuts relative to traditional bilateral repo arrangements. As of December 31, 2016, we had placed approximately $4.7 billion of repo financing at BES, providing further diversification of our funding sources and reducing our net interest expense. We anticipate transitioning a greater share of our repo funding to BES during 2017.
In the third quarter of 2016, our Board of Directors expanded our investment guidelines to include credit-sensitive assets, including CRT securities issued by the GSEs and other third parties. We believe CRT securities provide a compelling opportunity to invest in conforming credit, which has previously been the exclusive purview of the GSEs, and could provide incremental returns to our existing Agency RMBS investments over the longer term.
Our net asset value declined to $21.17 per common share as of December 31, 2016, from $22.59 per common share as of December 31, 2015. Our tangible net book value per common share was $19.50 per common share as of December 31, 2016. The loss in our net asset value was predominately a result of wider spreads on agency MBS relative to benchmark interest rates and the large increase in interest rates experienced during the fourth quarter.
Our economic return on common equity was 3.9% for 2016, comprised of dividends declared per common share of $2.30 and a loss in net asset value of $1.42 per common share. Our total return on our common stock, which includes stock price appreciation and dividend reinvestments, was 18.2% for the year.
The widening of Agency RMBS spreads and favorable funding dynamics that occurred over the course of 2016 have improved the risk-adjusted returns on Agency RMBS investments. In addition, with AGNC’s recent expansion into credit-sensitive investments, we believe that opportunistic investments in CRT securities can provide incremental returns that are less correlated with the interest rate exposure inherent in our Agency RMBS portfolio. Portfolio returns could be further supported by either higher leverage or a reduction in aggregate hedge or funding cost.
Finally, on July 1, 2016, we completed the acquisition of our external Manager, AMM, thereby internalizing our management, which lowers our operating costs and generates management fee income from managing MTGE.