Second, we have completed our share repurchase of 9.1 million shares since starting our buyback in the fourth quarter of last year.
The total buyback included repurchase of 3 million shares in the second quarter for $95.1 million.
Additionally, for the first time in our company's history, in the second quarter, we started leveraging our asset management partnerships to invest in single-family rental homes and middle market loans, consistent with ramping toward the AEL 2.0 asset allocation strategy.
During the quarter, we invested in 933 single family rental homes.
During the quarter, we allocated $104 million to middle market loans.
We expect middle market credit to be an important piece of the AEL 2.0 investment strategy.
This sub-segment of the market is a $4 billion per year product space historically dominated by two of our competitors.
We are committed to continue to introduce new products as we move through the AEL 2.0 transformation, which will help us compete effectively and grow our share of the annuity market.
Moving onto business results for the second quarter, total sales of $1.2 billion were down sequentially as expected versus the all-time record we set of $2.4 billion in the first quarter of this year.
As we discussed on the last call, we are focused on our fixed index annuity products, For the second quarter, FIA sales increased 33% sequentially to $887 million.
At American Equity Life, fixed index annuity sales increased 36% to $703 million from $517 million sequentially, as the refreshed AssetShield series continued to see increased momentum, led by a sequential 206% increase in AssetShield deposits.
In the quarter, the three proprietary indices we introduced to AssetShield, as part of our February refresh, the Credit Suisse Tech Edge Index, the Societe Generale Global Sentiment Index, and the Bank of America Destinations Index, accounted for 77% of second quarter AssetShield deposits.
FIA sales at Eagle Life of $185 million represented a 24% increase versus the first quarter of 2021, and a 155% increase compared to the year ago quarter.
Plus, the CEO has set a new Director retirement age at 75 years and has modified the membership and structure of its committees.
The net unrealized gain position improved by $1.2 billion in the quarter ending at $4.8 billion.
At June 30, we held $10 billion of cash and equivalents in the insurance company portfolios.
The current point in time yield on the portfolio, including excess cash, is still approximately 3.3%, so the pressure on investment spread will continue into the third quarter.
After completion of reinsurance transactions and the redeployment of remaining cash in excess of our target, we estimate the yield on our investment portfolio would still have been approximately 4%.
We are taking solid steps in the execution of our strategy to add $1 billion to $2 billion in privately sourced assets this year, growing to a pace of 5% or greater, of the portfolio in each subsequent year, to achieve an allocation of 30% or greater in privately sourced assets.
Year-to-date we have allocated approximately $800 million to privately sourced assets, including residential mortgage loans, single-family rental homes, commercial mortgage and agriculture loans, and middle market loans.
For the second quarter of 2021, the expected return on long-term investments acquired net of third party investment management fees, was approximately 4.15% compared to 3.74% in the first quarter.
We purchased $1.1 billion of long-term fixed income securities at a rate of 3.3% and $569 million of privately sourced assets at an expected return of 5.67%.
For the second quarter of 2021, we reported non-GAAP operating income of $93.8 million or $0.98 per diluted common share, compared to $93.1 million or $1.01 per share for the second quarter of 2020.
Average yield or invested assets was 3.51% in the second quarter of 2021 compared to 3.58% for this year's first quarter.
Cash and equivalents in the investment portfolio average $10 billion over the second quarter, up from $8.6 billion for this year's first quarter.
The aggregate cost of money for annuity liabilities was 156 basis points, down two basis points from the first quarter of this year.
Investment spread in the second quarter was 195 basis points, down five basis points from the first quarter.
Excluding non-trendable items, adjusted spread in the quarter was 181 basis points compared to 187 basis points for the first quarter.
The cost of options was up slightly to 147 basis points from 145 basis points in the first quarter of 2020, primarily reflecting an increase in the cost of PK options hedging our monthly point to point strategies due to the decrease in volatility over the quarter.
Monthly point to point remains our largest hedge strategy at just over 25% of notional.
Should the yields available to us decrease, or the cost of money rise, we have the flexibility to reduce our rates, if necessary, and could decrease our cost of money by roughly 58 basis points, if we reduce current rates to guaranteed minimums.
This is up slightly from 57 basis points we cited on our first quarter call.
The liability for Lifetime Income Benefit Riders, increased $34 million this quarter, after net positive experience, an adjustment of $29 million relative to our modeled expectations.
Deferred acquisition cost and deferred sales inducement amortization totaled $101 million, $31 million less than modeled expectations due to lower than model investment spread and benefit from high level of equity index credits.
Other operating costs and expenses increased to $65 million from $56 million in the first quarter.
Operating costs in the second quarter included $5 million of expenses associated with talent transition.
Total debt -- total capitalization, excluding accumulated other comprehensive income at the quarter-end was 11.9% compared to 12.2% at year-end and 14.7% in last year's comparable quarter.
At June 30, cash and equivalents at the holding company were in excess of our target by $330 million.
Finally, we have $236 million of share repurchase authorization remaining under the current plan approved by the Board of Directors in October 2020.

Summary:
Moving onto business results for the second quarter, total sales of $1.2 billion were down sequentially as expected versus the all-time record we set of $2.4 billion in the first quarter of this year.
The net unrealized gain position improved by $1.2 billion in the quarter ending at $4.8 billion.
For the second quarter of 2021, we reported non-GAAP operating income of $93.8 million or $0.98 per diluted common share, compared to $93.1 million or $1.01 per share for the second quarter of 2020.