Andrew C. Wiechmann
Chief Financial Officer at MSCI
Thanks, Bear. And hi, everyone. I continue to be really encouraged by the resilience of our results and the momentum we're seeing across product areas. Index subscription run-rate growth with asset managers and asset owners was almost 7% and 12% respectively. These client segments comprise nearly 70% of our index subscription run-rates. Among hedge funds and broker-dealers, we drove 22% and 8% index subscription run-rate growth, respectively in the 4th-quarter. Custom indexes and special packages grew 8% versus last year. Within the category, our custom index subscription run-rate growth was mid-teens, while we had a lower contribution from special packages.
And overall retention rate in index was 95% with a retention rate of almost 96% with asset managers. Within asset-based fees, global cash inflows into equity ETFs linked to MSCI indexes was $48 billion in the quarter, with particular strength in ETFs linked to developed markets outside the US, ESG and climate and factors. Q4 cash inflows into ETF products linked to MSCI, ESG and Climate Indexes reached nearly $12 billion, our highest quarterly cash inflows since the first-quarter of 2022. These inflows accounted for nearly 70% of global cash inflows into ESG and Climate Equity ETF products in the 4th-quarter.
AUM and ETF and non-ETF products linked to MSCI Climate Equity Indexes grew by more than 50% from last year, driven by strong inflows into ETFs and a few key mandate wins from asset owners. Meanwhile, inflows into ETF products linked to MSCI factor indexes were almost $6 billion, with solid inflows into quality, value growth and momentum factors. These MSCI factor index-linked ETF inflows were the highest quarterly flows since the second-quarter of 2021.
In Analytics, subscription run-rate growth was 7%, excluding the impact of foreign currency and was supported by the large wealth and fixed-income mandates previously mentioned. Analytics organic revenue growth was approximately 5% in the quarter. As we previously indicated, the revenue growth was impacted by the timing of implementation-related revenues compared to a year-ago. The release of subscription revenues related to implementations can be lumpy and will fluctuate from period-to-period. Near-term, we continue to expect recurring revenue growth rates will be slightly below run-rate growth as we compare to periods with higher concentrations of these revenues a year-ago.,
In our ESG and Climate Reportable segment, subscription run-rate growth was 10%, which excludes the impact of FX. Excluding FX headwinds, the subscription run-rate growth for the segment was 14% in Europe, 11% in Asia and 4% in the Americas. Our retention rate for the segment was over 93%, with most of the cancels reflecting client down sales and not outright terminations., the multi-year investments we've made in data quality and new content and capabilities like biodiversity, nature, regulatory solutions and geospatial supported recent wins. In general, across our ESG and climate franchise, we are benefiting from the breadth of our offering, data quality, large and comprehensive securities coverage across asset classes and the interoperability across MSCI products and frameworks.
In private capital Solutions, run-rate growth was 15% over the same-period last year and we had a retention rate of 92%. In real assets, new recurring subscription sales improved, although we had some large cancels related to client events and vendor consolidation, particularly among developers, brokers and agents. We had very strong free-cash flow-in 2024, up 21% with some improvement in collection cycles in Q4, our capital position remains strong with gross leverage of 2.6 times 2024 EBITDA, and we continue to be laser-focused on continuing to create value through disciplined capital allocation.
Turning to our 2025 guidance, which we published earlier this morning, our expense outlook assumes gradually increasing market levels throughout the year and reflects the ongoing reinvestments we make back into our business to fuel future growth and efficiencies. As we've seen in previous years, we expect adjusted EBITDA expenses to be about $35 million higher sequentially in Q1 2025 compared to Q4 of 2024, mostly driven by elevated compensation and benefits-related expenses.
Our capex guidance reflects our investments in software development across most parts of the business. Free-cash flow guidance reflects higher cash tax payments in Q1, some of which we deferred during 2024. As a reminder, our 2024 free-cash flow reflected cash tax timing impacts, of which about $30 million is resulting in elevated payments in 2025. Our interest expense guidance assumes our current debt levels and does not assume additional financings. We expect our Q1 effective tax-rate to include a benefit from discrete items. Beyond Q1, we expect a quarterly operating effective tax-rate of 19% to 21%.
We're looking-forward to an exciting year ahead. Our financial success and investments from 2024 provide a strong foundation for us to drive further growth in 2025. We have numerous large opportunities that we are poised to capitalize on.
And with that, operator, please open the line for questions.