During the second quarter, the S&P 500 continued to rise on the growing dominance of the FANG stocks which now represent almost 13% of the index's market cap and 4.3% of the 500 companies earnings.
15 months ago our focus value strategy posted the best absolute 10 year performance record in its history.
While our most recent 10 year history is more representative of our long-term average.
Meanwhile, the S&P 500s most recent 10 year record is substantially above it's average and appears to be anomalously high.
When we calculate a sharp ratio using our recent performance record and our higher short-term volatility, our investment skill appears questionable versus the S&P 500.
However, when we do the same calculation using average 10 year returns and the volatility of those 10 year returns, we see a completely different picture which one actually represents our true investment skill after 25 years of deep value investing.
We finished the quarter with approximately $400 million in net outflows.
For the previous 12 months, we had net positive flows of approximately $300 million.
We reported diluted earnings of $0.13 per share for the second quarter compared to zero last quarter and $0.18 per share for the second quarter of last year.
Revenues were $30.1 million for the quarter and operating income was $11 million.
Our operating margin was 36.4% this quarter, increasing from 32.1% last quarter and decreasing from 46.4% in the second quarter of last year.
We ended the quarter at $31.5 billion, up 17.5% from last quarter, which ended at $26.8 billion and down 15.5% from the second quarter of last year which ended at $37.3 billion.
The increase in assets under management from last quarter, was driven by market appreciation including the impact of foreign exchange of $5.1 billion, partially offset by net outflows of $0.4 billion.
The decrease from the second quarter of last year reflects $6.1 billion in market depreciation, including the impact of foreign exchange, partially offset by net inflows of $0.3 billion.
At June 30, 2020, our assets under management consisted of $13 billion in separately managed accounts.
$16.4 billion in sub-advised accounts and $2.1 million in our Pzena Funds.
Compared to last quarter, assets under management across all channels increased with separately managed account assets reflecting $2 billion in market appreciation and foreign exchange impact and $0.2 billion in net inflows.
Sub-advised account assets reflecting $2.8 billion in market appreciation and foreign exchange impact, partially offset by $0.7 billion in net outflows.
And assets in Pzena Funds being $0.3 billion in market appreciation and $0.1 billion in net inflows.
Average assets under management for the second quarter of 2020 were $29.8 billion, a decrease of 15.8% from last quarter and a decrease of 19.7% from the second quarter of last year.
Revenues decreased 13.1% from last quarter and 20.4% from the second quarter of last year.
During the quarter, we did not recognize any performance fees, similar to last quarter and compared to $0.3 million recognized in the second quarter of last year.
Our weighted average fee rate was 40.4 basis points for the quarter, compared to 39.1 basis points last quarter and 40.8 basis points for the second quarter of last year.
Our weighted average fee rate for separately managed accounts was 55.2 basis points for the quarter, compared to 52.6 basis points last quarter and 54.5 basis points for the second quarter of last year.
Our weighted average fee rate for sub-advised accounts was 26 basis points for the quarter, compared to 26.6 basis points for last quarter and 28.7 basis points for the second quarter of last year.
During each of the second and first quarters of 2020, we recognized $1 million reduction in base fees related to these accounts, compared to a $0.5 million reduction in base fees during the second quarter of last year.
Our weighted average fee rate for Pzena Funds was 65.9 basis points for the quarter, increasing from 62.5 basis points last quarter and decreasing from 69.4 basis points for the second quarter of last year.
Looking at operating expenses, our compensation and benefits expense was $15.6 million for the quarter, decreasing from $19.1 million last quarter and from $16 million for the second quarter of last year.
G&A expenses were $3.6 million for the second quarter of 2020, compared to $4.4 million last quarter and $4.3 million for the second quarter of last year.
Other income was $3.2 million for the quarter, driven primarily by the performance of our investments.
The effective rate for our unincorporated and other business taxes was 4.1% this quarter compared to 29.9% last quarter and 4.3% in the second quarter of last year.
We expect the effective rate associated with the unincorporated and other business taxes of our operating company to be between 3% and 5% on an ongoing basis.
Our effective tax rate for our corporate income taxes ex-UBT and other business taxes was 26.6% this quarter, compared to our effective tax rate of 100% last quarter and 23.8% for the second quarter of last year.
We expect this rate to be between 23% and 25% on an ongoing basis.
The allocation to the nonpublic members of our operating company was approximately 77.7% of the operating company's net income for the second quarter of 2020, compared to 74.5% both last quarter and in the second quarter of last year.
During the quarter, through our stock buyback program, we repurchased and retired approximately 266,000 shares of Class A common stock for $1.4 million.
At June 30, there was approximately $11.2 million remaining in the repurchase program.
At quarter end, our financial position remains strong with $33.1 million in cash and cash equivalents as well as $7.3 million in short-term investments.
We declared a $0.03 per share quarterly dividend last night.

Summary:
We reported diluted earnings of $0.13 per share for the second quarter compared to zero last quarter and $0.18 per share for the second quarter of last year.
Revenues were $30.1 million for the quarter and operating income was $11 million.