What was the overall average commission per cleared commissionable order in the second quarter of 2021
mless back office functionality critical for brokers who want to provide a global offering in order to capture clients worldwide who seek to invest and want to be able to access many markets in order to do so.
We continue to be excited about 2021 and beyond. I know you were all going to ask me about a Bitcoin introduction and we expected by the end of next month. In other areas, we've provided content to Coursera, creating a certificate program for them called A Practical Guide to Trading, which covers equities, forex, US bond and derivatives trading. You should also take a look at IBKR Campus, which offers over 50 courses on investment products, trading tools and portfolio and risk analysis. We want informed clients who will have the knowledge and tools to be with us for the long run.
And finally, we look forward to the Robinhood IPO so that our various metrics can be compared to another firm besides Charles Schwab.
With that, I will turn the call over to our CFO, Paul Brody, who will go through the numbers for the quarter. Paul?
Paul J. Brody -- Chief Financial Officer, Treasurer, Secretary and Director
Thank you, Nancy. Thanks, everyone, for joining the call. As usual, we'll review the quarterly operating results, the non-core items, factors that drove those numbers and then we will open it up for questions.
Starting with the operating data. Progressively stronger trading levels and record margin borrowing throughout the quarter drove robust operating metrics albeit below the unusual spike in the first quarter with the tailwind of rising world markets on positive vaccination and economic news and low interest rate.
Continued global interest in financial markets amid the search for higher yield led to industry trading volumes that are still above the activity levels in 2020 in most products. Mean stock trading volume came down from the extreme highs of the first quarter which impacted industry volume mainly in stock. So, over the course of the second quarter, trading by our active trader customer base rose from April lows.
Volatility, as measured by the average VIX, fell from the unusually high levels that reached early last year at the beginning of the first phase of the coronavirus pandemic, a time of great uncertainty amid rising case numbers worldwide. The average VIX fell from 35% in the second quarter last year to 18% this quarter. And while it has come down recently, the VIX is still stronger than pre-pandemic levels, reflecting perhaps the unevenness of the reopening of economies worldwide.
Merit to the second quarter of 2020, our quarterly total DARTs rose 32% to $2.3 million, second only to the unusually active first quarter. Our customer trade volumes rose year-on-year in several product classes, led by increases of 34% and 160% in options and stock volumes respectively. Stock volume was inflated by trading in low priced stocks, though even after removing those from our calculation, our share volume still rose 36%. Again, these volumes are second only to those of the first quarter.
Futures volume declined 19% year-on-year, but remained modestly higher than the pre-pandemic level. FX dollar volumes this quarter were lower, a trend we have seen since the explosion of volume in early 2020 and now are about even with pre-pandemic levels.
Total accounts reached a record 1,414,000, up 61% over the prior year, contributing to customer equity, growing 79% from the second quarter of 2020 to $363.5 billion.
Our overall average commission per cleared commissionable order declined 15% versus last year to $2.38, so it rose 3% versus first quarter. Factors impacting this decline include a product mix that featured smaller average trade size as an options forex and our continued success in capturing liquidity rebate, some or all of which are passed through to our clients. Capturing these rebates reduces the overall commission our clients pay, decreasing the average commission per DART, but also reduces the exchange fees we pay on the expense side, making their net impact neutral to our bottom line.
Moving to our net intere
mless back office functionality critical for brokers who want to provide a global offering in order to capture clients worldwide who seek to invest and want to be able to access many markets in order to do so.
We continue to be excited about 2021 and beyond. I know you were all going to ask me about a Bitcoin introduction and we expected by the end of next month. In other areas, we've provided content to Coursera, creating a certificate program for them called A Practical Guide to Trading, which covers equities, forex, US bond and derivatives trading. You should also take a look at IBKR Campus, which offers over 50 courses on investment products, trading tools and portfolio and risk analysis. We want informed clients who will have the knowledge and tools to be with us for the long run.
And finally, we look forward to the Robinhood IPO so that our various metrics can be compared to another firm besides Charles Schwab.
With that, I will turn the call over to our CFO, Paul Brody, who will go through the numbers for the quarter. Paul?
Paul J. Brody -- Chief Financial Officer, Treasurer, Secretary and Director
Thank you, Nancy. Thanks, everyone, for joining the call. As usual, we'll review the quarterly operating results, the non-core items, factors that drove those numbers and then we will open it up for questions.
Starting with the operating data. Progressively stronger trading levels and record margin borrowing throughout the quarter drove robust operating metrics albeit below the unusual spike in the first quarter with the tailwind of rising world markets on positive vaccination and economic news and low interest rate.
Continued global interest in financial markets amid the search for higher yield led to industry trading volumes that are still above the activity levels in 2020 in most products. Mean stock trading volume came down from the extreme highs of the first quarter which impacted industry volume mainly in stock. So, over the course of the second quarter, trading by our active trader customer base rose from April lows.
Volatility, as measured by the average VIX, fell from the unusually high levels that reached early last year at the beginning of the first phase of the coronavirus pandemic, a time of great uncertainty amid rising case numbers worldwide. The average VIX fell from 35% in the second quarter last year to 18% this quarter. And while it has come down recently, the VIX is still stronger than pre-pandemic levels, reflecting perhaps the unevenness of the reopening of economies worldwide.
 Merit to the second quarter of 2020, our quarterly total DARTs rose 32% to $2.3 million, second only to the unusually active first quarter. Our customer trade volumes rose year-on-year in several product classes, led by increases of 34% and 160% in options and stock volumes respectively. Stock volume was inflated by trading in low priced stocks, though even after removing those from our calculation, our share volume still rose 36%. Again, these volumes are second only to those of the first quarter.
Futures volume declined 19% year-on-year, but remained modestly higher than the pre-pandemic level. FX dollar volumes this quarter were lower, a trend we have seen since the explosion of volume in early 2020 and now are about even with pre-pandemic levels.
Total accounts reached a record 1,414,000, up 61% over the prior year, contributing to customer equity, growing 79% from the second quarter of 2020 to $363.5 billion.
Our overall average commission per cleared commissionable order declined 15% versus last year to $2.38, so it rose 3% versus first quarter. Factors impacting this decline include a product mix that featured smaller average trade size as an options forex and our continued success in capturing liquidity rebate, some or all of which are passed through to our clients. Capturing these rebates reduces the overall commission our clients pay, decreasing the average commission per DART, but also reduces the exchange fees we pay on the expense side, making their net impact neutral to our bottom line.
Moving to our net intere