Management’s Discussion and Analysis of Financial Condition and Results of Operations–(Continued) Life and annuity contract benefits increased 1.2% or $19 million in 2007 compared to 2006 due to increased contract benefits on life insurance products, partially offset by lower contract benefits on annuities.
Increased contract benefits on life insurance products in 2007 were primarily due to unfavorable mortality experience, litigation related costs recognized in 2007 in the form of additional policy benefits on certain universal life policies written prior to 1992, and higher contract benefits associated with the Workplace Division.
The decline in contract benefits on annuities was mostly attributable to favorable mortality experience on immediate annuities with life contingencies and the absence in 2007 of contract benefits on the reinsured variable annuity business, partially offset by an increase in the implied interest on immediate annuities with life contingencies.
We analyze our mortality and morbidity results using the difference between premiums and contract charges earned for the cost of insurance and life and annuity contract benefits excluding the portion related to the implied interest on immediate annuities with life contingencies (‘‘benefit spread’’).
This implied interest totaled $552 million, $547 million and $539 million in 2008, 2007 and 2006, respectively.
The benefit spread by product group is disclosed in the following table.
## Table 0 ##
Interest credited to contractholder funds decreased 10.1% or $270 million in 2008 compared to 2007 and increased 2.8% or $72 million in 2007 compared to 2006.
The decrease in 2008 compared to 2007 was due primarily to a decline in average contractholder funds, decreased weighted average interest crediting rates on institutional products resulting from a decline in market interest rates on floating rate obligations, and a favorable change in amortization of DSI relating to realized capital gains and losses, partially offset by the acceleration of amortization of DSI due to changes in assumptions.
The acceleration of amortization of DSI due to changes in assumptions increased interest credited to contractholder funds by $70 million in 2008 compared to amortization deceleration which decreased interest credited to contractholder funds by $5 million in 2007.
The increase in interest credited to contractholder funds in 2007 compared to 2006 was due primarily to growth in average contractholder funds and, to a lesser extent, higher weighted average interest crediting rates on institutional products, which are detailed in the table of investment yields, crediting rates and investment spreads by product below.
The increase was partially offset by the impact of the reinsured variable annuity business.
Excluding the impact of the reinsured variable annuity business, interest credited to contractholder funds increased 3.7% in 2007 compared to 2006.
In order to analyze the impact of net investment income and interest credited to contractholders on net income, we monitor the difference between net investment income and the sum of interest credited to contractholder funds and the implied interest on immediate annuities with life contingencies, which is included as a component of life and annuity contract benefits on the Consolidated Statements of Operations (‘‘investment spread’’).
The investment spread by product group is shown in the following table.
## Table 1 ##
Certain collateralized securities are detailed in the following table by Moody’s equivalent rating as of December 31, 2008.
## Table 2 ##
During 2008, certain financial markets continued to experience price declines due to market and liquidity disruptions.
We experienced this illiquidity and disruption in certain of our MBS, CMBS and ABS fixed income securities, particularly in our Prime residential mortgage-backed securities (‘‘Prime’’), Alt-A, CMBS, CRE CDO, ABS RMBS, ABS CDO and other collateralized debt obligations (‘‘other CDO’’) portfolios.
These portfolios totaled $7.90 billion, or approximately 8% of our total investments at December 31, 2008.
Other securities markets, including certain other asset-backed and real estate-backed securities markets, also experienced illiquidity, but to a lesser degree.
We determine the fair values of securities comprising these illiquid portfolios by obtaining information from an independent third-party valuation service provider and brokers.
We confirmed the reasonableness of the fair value of these portfolios as of December 31, 2008 by analyzing available market information including, but not limited to, collateral quality, anticipated cash flows, credit enhancements, default rates, loss severities, securities’ relative position within their respective capital structures, and credit ratings from statistical rating agencies.
those in the United States, and initial voice networks continue to be deployed in underdeveloped areas.
A majority of consumers in these markets still utilize basic wireless services, predominantly on feature phones, while advanced device penetration remains low.
In more developed urban locations within these markets, early-stage data network deployments are underway.
Carriers are focused on completing voice network build-outs while also investing in initial data networks as wireless data usage and smartphone penetration within their customer bases begin to accelerate.
In markets with rapidly evolving network technology, such as South Africa and most of the countries in Latin America where we do business, initial voice networks, for the most part, have already been built out, and carriers are focused on 3G and 4G network build outs.
Consumers in these regions are increasingly adopting smartphones and other advanced devices, and, as a result, the usage of bandwidth-intensive mobile applications is growing materially.
Recent spectrum auctions in these rapidly evolving markets have allowed incumbent carriers to accelerate their data network deployments and have also enabled new entrants to begin initial investments in data networks.
Smartphone penetration and wireless data usage in these markets are growing rapidly, which typically requires that carriers continue to invest in their networks in order to maintain and augment their quality of service.
Finally, in markets with more mature network technology, such as Germany and France, carriers are focused on deploying 4G data networks to account for rapidly increasing wireless data usage among their customer base.
With higher smartphone and advanced device penetration and significantly higher per capita data usage, carrier investment in networks is focused on 4G coverage and capacity.
We believe that the network technology migration we have seen in the United States, which has led to significantly denser networks and meaningful new business commencements for us over a number of years, will ultimately be replicated in our less advanced international markets.
As a result, we expect to be able to leverage our extensive international portfolio of approximately 104,470 communications sites and the relationships we have built with our carrier customers to drive sustainable, long-term growth.
We have master lease agreements with certain of our tenants that provide for consistent, long-term revenue and reduce the likelihood of churn.
Our master lease agreements build and augment strong strategic partnerships with our tenants and have significantly reduced colocation cycle times, thereby providing our tenants with the ability to rapidly and efficiently deploy equipment on our sites.
Property Operations New Site Revenue Growth.
During the year ended December 31, 2016, we grew our portfolio of communications real estate through the acquisition and construction of approximately 45,310 sites.
In a majority of our Asia, EMEA and Latin America markets, the revenue generated from newly acquired or constructed sites resulted in increases in both tenant and pass-through revenues (such as ground rent or power and fuel costs) and expenses.
We continue to evaluate opportunities to acquire communications real estate portfolios, both domestically and internationally, to determine whether they meet our risk-adjusted hurdle rates and whether we believe we can effectively integrate them into our existing portfolio.

<table><tr><td> ($ in millions) </td><td>2008</td><td>2007</td><td>2006</td></tr><tr><td>Life insurance</td><td>$540</td><td>$515</td><td>$549</td></tr><tr><td>Annuities</td><td>-62</td><td>-35</td><td>-43</td></tr><tr><td>Total benefit spread</td><td>$478</td><td>$480</td><td>$506</td></tr></table>
<table><tr><td> ($ in millions) </td><td> 2008</td><td> 2007</td><td> 2006</td></tr><tr><td>Annuities</td><td>$389</td><td>$505</td><td>$481</td></tr><tr><td>Life insurance</td><td>60</td><td>63</td><td>60</td></tr><tr><td>Institutional products</td><td>71</td><td>87</td><td>88</td></tr><tr><td>Bank</td><td>22</td><td>18</td><td>16</td></tr><tr><td>Net investment income on investments supporting capital</td><td>306</td><td>396</td><td>380</td></tr><tr><td>Total investment spread</td><td>$848</td><td>$1,069</td><td>$1,025</td></tr></table>
<table><tr><td> ($ in millions) </td><td> Fair value at December 31, 2008</td><td>% to Total investments</td><td>Aaa</td><td>Aa</td><td>A</td><td>Baa</td><td> Ba or lower</td></tr><tr><td> MBS</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>U.S. Agency</td><td>$3,284</td><td>3.4%</td><td>100.0%</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Prime</td><td>621</td><td>0.7</td><td>89.5</td><td>6.0%</td><td>2.6%</td><td>1.9%</td><td>—</td></tr><tr><td>Alt-A</td><td>582</td><td>0.6</td><td>75.9</td><td>5.1</td><td>0.9</td><td>2.1</td><td>16.0%</td></tr><tr><td>Other</td><td>5</td><td>—</td><td>—</td><td>100.0</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Total MBS</td><td>$4,492</td><td>4.7%</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td> CMBS</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>CMBS</td><td>$3,819</td><td>4.0%</td><td>90.3</td><td>7.7</td><td>0.9</td><td>1.0</td><td>0.1</td></tr><tr><td>Commercial real estate collateralized debt obligations ("CRE CDO")</td><td>27</td><td>—</td><td>—</td><td>29.6</td><td>37.1</td><td>29.6</td><td>3.7</td></tr><tr><td>Total CMBS</td><td>$3,846</td><td>4.0%</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td> ABS</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>ABS RMBS non-insured</td><td>$1,641</td><td>1.7%</td><td>45.8</td><td>29.4</td><td>10.2</td><td>6.7</td><td>7.9</td></tr><tr><td>ABS RMBS insured</td><td>426</td><td>0.4</td><td>0.9</td><td>13.8</td><td>1.9</td><td>49.8</td><td>33.6</td></tr><tr><td>Total ABS RMBS</td><td>2,067</td><td>2.1</td><td>36.5</td><td>26.2</td><td>8.5</td><td>15.5</td><td>13.3</td></tr><tr><td>Asset-backed collateralized debt obligations ("ABS CDO")</td><td>6</td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td><td>100.0</td></tr><tr><td>Total asset-backed securities collateralized by sub-prime residential mortgage loans</td><td>2,073</td><td>2.1</td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Other collateralized debt obligations:</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>Cash flow CLO</td><td>501</td><td>0.5</td><td>50.6</td><td>21.0</td><td>19.4</td><td>6.0</td><td>3.0</td></tr><tr><td>Synthetic CDO</td><td>47</td><td>0.1</td><td>6.4</td><td>34.0</td><td>—</td><td>46.8</td><td>12.8</td></tr><tr><td>Trust preferred CDO</td><td>74</td><td>0.1</td><td>2.7</td><td>75.6</td><td>14.9</td><td>4.1</td><td>2.7</td></tr><tr><td>Market value CDO</td><td>28</td><td>—</td><td>—</td><td>28.6</td><td>10.7</td><td>7.1</td><td>53.6</td></tr><tr><td>Project finance CDO</td><td>44</td><td>—</td><td>—</td><td>25.0</td><td>56.8</td><td>18.2</td><td>—</td></tr><tr><td>CDOs that invest in other CDOs ("CDO squared")</td><td>10</td><td>—</td><td>—</td><td>—</td><td>60.0</td><td>40.0</td><td>—</td></tr><tr><td>Collateralized bond obligations</td><td>24</td><td>—</td><td>—</td><td>—</td><td>16.7</td><td>45.8</td><td>37.5</td></tr><tr><td>Other CLO</td><td>50</td><td>0.1</td><td>100.0</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Total other collateralized debt obligations</td><td>778</td><td>0.8</td><td>39.7</td><td>25.2</td><td>18.8</td><td>10.3</td><td>6.0</td></tr><tr><td>Other asset-backed securities</td><td>1,009</td><td>1.1</td><td>42.0</td><td>10.8</td><td>22.3</td><td>19.2</td><td>5.7</td></tr><tr><td>Total ABS</td><td>$3,860</td><td>4.0%</td><td></td><td></td><td></td><td></td><td></td></tr></table>

Question: what is the highest total amount of Cash flow CLO? (in million)
Answer: 501