An extensive list of these risks and uncertainties are identified in our annual report on Form 10-K for the fiscal year ended August 31, 2020 and other filings.
In stepping back and reflecting for a moment, it's hard to believe that 12 months have passed since we first encountered COVID.
The team delivered core earnings per share of $1.27 and revenue of $6.8 billion, resulting in a core operating margin of 4.2%.
Moving to Slide 7, I'll address our updated outlook for the year.
We now believe core earnings will be in the neighborhood of $5 a share, an increase of 25% from what we anticipated back in September, with top-line revenue coming in around $28.5 billion.
This incremental revenue improves our portfolio as evidenced by another 10-basis-point increase to core operating margin, which we now forecast to be 4.2% for the year.
Lastly, we remain committed to generating a minimum of $600 million in free cash flow, a testament to how we're managing our capital investments.
Given the additional revenue, I am particularly pleased with the strong leverage we achieved during the quarter which enabled us to deliver a strong core operating margin of 4.2%.
Putting it all together on the next slide, net revenue for the second quarter was $6.8 billion, $300 million above the midpoint of our guidance range.
On a year-over-year basis, revenue increased by $700 million or 11%.
GAAP operating income was $236 million and the GAAP diluted earnings per share was $0.99.
Core operating income during the quarter was $285 million, an increase of 78% year over year, representing a core operating margin of 4.2%, a 160-basis-point improvement over the prior year.
Net interest expense in Q2 was $33 million and core tax rate came in at approximately 23%.
Core diluted earnings per share was $1.27, a 154% improvement over the prior-year quarter.
Revenue for our DMS segment was $3.6 billion, an increase of 26% on a year-over-year basis.
Core margins for the segment came in at an impressive 5.1%, 210 basis points higher than the previous year.
Revenue for our EMS segment was $3.2 billion, also reflecting strong broad-based demand.
Core margins for the segment were 3.1%, 80 basis points over the prior year.
Cash flows provided by operations were $20 million in Q2 and capital expenditures net of customer co-investments total $152 million.
We exited the quarter with a cash balance of $838 million.
We ended Q2 with committed capacity under the global credit facilities of $3.8 billion.
With this available capacity, along with our quarter-end cash balance, Jabil ended Q2 with access to more than $4.6 billion of available liquidity, which we believe provides us ample flexibility.
During Q2, we repurchased approximately 1.9 million shares or $82 million.
At the end of the quarter, $254 million remain outstanding in our current stock repurchase authorization and we intend to complete this authorization during the second half of FY '21 as we remain committed to returning capital to shareholders.
DMS segment revenue is expected to increase 19% on a year-over-year basis to $3.5 billion.
EMS segment revenue is expected to be $3.4 billion, an increase of 1% on a year-over-year basis.
We expect total company revenue in the third quarter of fiscal '21 to be in the range of $6.6 billion to $7.2 billion for an increase of 9% on a year-over-year basis at the midpoint of the range.
Core operating income is estimated to be in the range of $220 million to $270 million.
Core diluted earnings per share is estimated to be in the range of $0.90 to $1.10.
GAAP diluted earnings per share is expected to be in the range of $0.69 to $0.89.
Today, electric vehicles account for less than 2% of total vehicles in the market.
Jabil's long-standing capabilities and over 10 years of experience and credibility in this space has positioned us extremely well to benefit from this ongoing trend.
We now expect core operating margins to be 4.2% on revenue of approximately $28.5 billion.
This improved outlook translates to core earnings per share of approximately $5.
And importantly, despite the stronger growth, we remain committed to delivering free cash flow in excess of $600 million for the year.

Summary:
The team delivered core earnings per share of $1.27 and revenue of $6.8 billion, resulting in a core operating margin of 4.2%.
Moving to Slide 7, I'll address our updated outlook for the year.
We now believe core earnings will be in the neighborhood of $5 a share, an increase of 25% from what we anticipated back in September, with top-line revenue coming in around $28.5 billion.
GAAP operating income was $236 million and the GAAP diluted earnings per share was $0.99.
Core diluted earnings per share was $1.27, a 154% improvement over the prior-year quarter.
We expect total company revenue in the third quarter of fiscal '21 to be in the range of $6.6 billion to $7.2 billion for an increase of 9% on a year-over-year basis at the midpoint of the range.
Core diluted earnings per share is estimated to be in the range of $0.90 to $1.10.
GAAP diluted earnings per share is expected to be in the range of $0.69 to $0.89.