Jessica Fischer
Chief Financial Officer at Charter Communications
Thanks, Chris. Let's turn to our customer results on Slide 6. Including residential and SMB, we lost 149,000 Internet customers in the second quarter while, in mobile, we added 557,000 mobile lines. Video customers declined by 408,000 and wireline voice customers declined by 280,000. As Chris mentioned, our second quarter Internet losses were primarily driven by the end of the ACP program. ACP program connects ended in early February. In May, the program's original $30 subsidy was reduced to $14 and, in June, that subsidy was reduced to zero. We estimate that the end of the program's impact on our second quarter Internet gross additions and churn drove over 100,000 of our 149,000 Internet losses in the quarter.
And from a financial perspective, there was an approximately $30 million headwind to second quarter revenue from one-time, non-recurring ACP-related items in the quarter. In addition, similar to the end of the Keep Americans Connected program in June 2020, many of our ACP customers had past due balances that had been fully reserved for accounting purposes. We took steps to eliminate a portion of those back balances for certain customers and put a portion of the remaining balances on payment plans. For certain customers with a low likelihood to pay post ACP, we have been recognizing revenue on a cash basis, resulting in slightly less revenue and less bad debt in the second quarter than we would have otherwise had.
So far, we're performing well with ACP retention, but the largest driver of Internet customer losses associated with the end of the ACP program will be in non-pay disconnects, and they will occur in the third and fourth quarters, likely weighted to the third. We continue to do everything we can to preserve connectivity for former ACP subsidy recipients. We have a number of products and offers to assist those that have lost their ACP subsidy, including our Spectrum Internet Assist program, our Internet 100 product, and we've been offering all of our ACP customers a free mobile line for one year, and we continue to market offers targeted at low-income customers, a segment that we have historically served well.
Turning to rural. We ended the quarter with 582,000 subsidized rural passings. We grew those passings by 89,000 in the second quarter and by 345,000 over the last 12 months. We had 36,000 net customer additions in our subsidized rural footprint in the quarter. We continue to expect to activate approximately 450,000 new subsidized rural passings in 2024, about 50% more than in 2023. We also continue to expect our RDOF build to be completed by the end of 2026, two years ahead of schedule.
Moving to second quarter financial results, starting on Slide 7. Over the last year, residential customers declined by 1.3%. Residential revenue per customer relationship grew by 0.4% year over year, given promotional rate step-ups, rate adjustments, and the growth of Spectrum Mobile, partly offset by a higher mix of non-video customers, growth of lower-priced video packages within our base, and some Internet ARPU compression related to retention offers extended to customers that previously received an ACP subsidy. As Slide 7 shows, in total, residential revenue declined by 0.6% year over year.
Turning to commercial. SMB revenue grew by 0.6% year over year, reflecting SMB customer growth of 0.2% year over year and higher monthly SMB revenue per SMB customer, primarily due to rate adjustments. Enterprise revenue grew 4.5% year over year, driven by enterprise PSU growth of 6.1% year over year. And when excluding all wholesale revenue, enterprise grew by 5.9%. Second quarter advertising revenue grew by 3.3% year over year, given political revenue growth. Core ad revenue was down about 2% year over year. Other revenue grew by 6% year over year, primarily driven by higher mobile device sales. And in total, consolidated second quarter revenue was up 0.2% year over year and 0.1% year over year when excluding advertising revenue.
Moving to operating expenses and adjusted EBITDA on Slide 8. In the second quarter, total operating expenses declined by 1.4% year over year. Programming costs declined by 9.8% year over year due to a 9.5% decline in video customers year over year and a higher mix of lighter video packages, partly offset by higher programming rates. Other costs of revenue increased by 12.6%, primarily driven by mobile service direct costs and higher mobile device sales.
Cost to service customers declined 4.2% year over year, given productivity from our 10-year investments, including lower labor costs and lower bad debt expense as we saw some favorability in our mobile bad debt as a portion of revenue due to an improved customer tenure and credit profile. And as I mentioned earlier, a portion of our uncollectible billings offset revenue in the quarter. Sales and marketing costs grew by 1.9% as we remain focused on driving customer acquisition. Finally, other expense grew by 4.7%, mostly driven by an insurance expense benefit from the prior year quarter.
Adjusted EBITDA grew by 2.6% year over year in the quarter and when excluding advertising, EBITDA grew by 2.4% year over year. While we don't manage the business at a single product line P&L level, we continue to compute allocations internally. And this quarter, for the first time, our standalone mobile adjusted EBITDA was positive, even when including the headwind of subscriber acquisition costs and without the benefit of GAAP revenue allocation to mobile revenue. Our mobile profitability this quarter marks a significant milestone. It shows that we're on the path to establishing a mobile business that is very profitable.
Overall, our goal is to deliver solid EBITDA growth, and we believe we can continue to do that even as we make significant investments in the business and face a challenging competitive environment and the end of the ACP program. Our expense management process is working with growing realization of impacts in the second quarter. We continue to expect accelerating EBITDA growth in the back half of the year, given our expense management initiatives, Spectrum One promotional roll-off and political advertising revenue.
Turning to net income on Slide 9. We generated $1.2 billion of net income attributable to Charter shareholders in the second quarter, in line with last year, as higher adjusted EBITDA was mostly offset by higher other operating expense, primarily due to restructuring and severance costs and net amounts of litigation settlements.
Turning to Slide 10. Capital expenditures totaled $2.85 billion in the second quarter, in line with last year's second quarter spend. Line extension spend totaled $1.1 billion, $37 million higher than last year, driven by our subsidized rural construction initiative and continued network expansion across residential and commercial green sales and market fill-in opportunities. Second quarter capital expenditures, excluding line extensions, totaled $1.7 billion, which was similar to the prior year period.
For the full year 2024, we now expect capital expenditures to total approximately $12 billion, down from between $12.2 billion and $12.4 billion previously. Our reduced outlook for 2024 capital spending reflects lower Internet and video customer net additions, including the impact of the end of the ACP program, which drives lower CPE costs. We're also actively managing vendor rates and construction materials to make our capital expenditures more efficient. We still expect line extension spend of approximately $4.5 billion and network evolution spend of approximately $1.6 billion.
Turning to free cash flow on Slide 11. Free cash flow in the second quarter totaled $1.3 billion, an increase of approximately $630 million compared to last year's second quarter. The year-over-year increase was primarily driven by higher adjusted EBITDA, lower cash taxes due to timing and a favorable change in working capital. On that front, we've been managing the balance sheet to provide us better overall cash flow and increased flexibility.
Over the last several quarters, we sold our towers portfolio, which generated almost $400 million in proceeds. We launched our EIP securitization program in the second quarter, which backs a new $1.25 billion credit facility at favorable interest rates and we've been working with our vendor base to extend our payment terms, utilizing a supply chain financing tool to support our working capital favorability. We will continue to identify and capitalize on balance sheet opportunities to help fund our unique one-time capital investments.
We finished the quarter with $96.5 billion in debt principal. Our current run rate annualized cash interest is $5.1 billion and we repurchased 1.5 million Charter shares in Charter Holdings common units, totaling $404 million at an average price of $271 per share. Given our long-dated and 86% fixed rate debt structure, our sensitivity to higher rates is relatively low. If we refinanced all of our debt due in 2025 and 2026 at current rates, the impact to our run rate interest expense would be less than $60 million.
As of the end of the second quarter, our ratio of net debt to last 12 months adjusted EBITDA moved down to 4.32 times. We expect to continue to move closer to the middle of our 4 times to 4.5 times target leverage range through the end of this year and we remain fully committed to maintaining our split-rated debt structure, including access to the investment-grade market, given the significant benefits that it offers to all of our capital providers.
We continue to be confident in the long-term trajectory of the business. We have the best products at the best prices in our industry, and we remain underpenetrated relative to our long-term potential. That, combined with the investments that we're making in the business and our expense savings initiative, will continue to drive strong EBITDA growth and value creation for many years to come.
And with that, I'll turn it over to the operator for Q&A.