Guilherme Marques do Lago
Analyst
Thank you, David, and good evening, everyone. As David mentioned, we delivered a strong first quarter in both operating and financial KPIs. Those results were achieved by focusing on our simple yet powerful value-generating strategy, which can be summarized by 3 guiding pillars: First, a focus on growing our customer base in the 3 markets where we operate and rapidly converting our new customers into active customers; second, expanding average revenue per active customers, or ARPAC, through both cross-selling and upselling; and third, continuing to deliver high growth while maintaining one of the lowest operating costs in the industry.
Now let's delve further into our first quarter results to gain a deeper understanding on the progression of each one of these pillars. I will begin with the results of our customer acquisition. During the first quarter of 2024, our customer base continued to increase at a solid pace. We accelerated customer growth quarter-over-quarter, welcoming 5.5 million new customers in the first quarter of 2024 for a total of 99.3 million customers at quarter end, a 26% increase year-over-year.
In Brazil alone, our customer growth pace is at approximately 1.3 million customers per month with the vast majority still coming from referrals. This not only translates into lower acquisition costs, but also ensures faster activation, showcasing the trust and satisfaction our customers have in our services. Our client base in both Mexico and Colombia also experienced strong positive growth.
In Mexico, we reached 6.6 million customers this quarter, marking a remarkable 106% year-over-year growth and surpassing last quarter's net additions. Additionally, we now serve more than 900,000 customers in Colombia. Once we add customers, our goal is to activate and retain them. Our active customer base has increased by 27% year-over-year, followed by another sequential quarterly increase in the monthly activity rate, which now stands at 83.2%, up from 82.1% just 1 year ago. This marks the tenth consecutive increase in this metric. We believe that this is a testament to our proficiency in engaging customers effectively on our platform.
Turning our attention to revenue expansion. The first chart highlights that Nu has established primary banking relationships with around 59% of our active customer base. The drop of 2 percentage points in comparison to the fourth quarter of 2023 is mainly associated with last quarter's seasonality, considering increased transactionality during the month of December. Nevertheless, the 2 following charts show an increase in both the number of products per active customer and ARPAC.
As you can see in the second chart, the number of products per active customers grew from an average of 4 last quarter to 4.1 this quarter, illustrating our successful cross-selling strategy achieved by introducing new products to our customers and establishing ourselves as their primary banking partner. The last chart shows the combined effect of these 2 dynamics. By having significant customer engagement, as demonstrated in the first chart, together with our growing product cross-sell capabilities, as shown in the second chart, it produces increasingly positive results.
Our monthly ARPAC increased to $11.4 this quarter in comparison to $10.6 just 1 quarter ago. Our more mature cohorts are already generating a monthly ARPAC of $27. This reported increase in ARPAC resulted in another quarter of solid revenue growth as presented in the next slide. Our monthly ARPAC grew sequentially and accelerated its year-over-year expansion rate to 30%, reaching $11.4, up from $8.6 just 1 year ago. As discussed in prior earnings calls, we maintain confidence in further growing ARPAC going forward towards its full potential.
In the second chart, we illustrate our revenues hit a new record high this quarter, reaching $2.7 billion, up 64% year-over-year. Just a year ago, our revenue was $1.6 billion. This growth was driven by the increase in active clients, combined with higher ARPAC levels. Now let's discuss our cards business in more detail. It's important to remember that for cards, the purchase volumes are seasonal, higher in the fourth quarter and lower in the first quarter of every year. Historical seasonality analysis shows a drop of 6.9% on average in total purchase volume for the industry.
However, the sequential reduction in Nu's purchase volume this quarter was only 3.7%, with especially strong performance in credit cards, which contracted only 1.8% on an FX-neutral basis versus the historical industry seasonality drop of 5.9%. Compared to the first quarter of last year, our purchase volume was up 30% on an FX-neutral basis to $31.1 billion, sustaining its very strong growth path.
On the right side, the chart shows how purchase volumes expand as cohorts of customers develop and mature. Older cohorts continue to increase purchase volumes. While an initial disparity does exist between newer and older cohorts, both tend to exhibit an upward trend in consumption over time. We expect that the compounding effect of adding millions of customers each month, along with the maturation of new customers into historically observed spending patterns, will strongly support the growth of future purchase volumes at Nubank.
Talking about purchase volumes trend for the industry, we believe Nu ended the first quarter of 2024 with a market share of around 15%, including credit, debit and prepaid cards. As we continue to attract millions of new customers every quarter and their spending matures over time, our confidence in our ability to capture additional market shares in the future only grows.
This quarter, our consumer finance portfolio, comprising credit cards and personal loans, posted another acceleration, growing 52% year-over-year and reaching $19.6 billion. This growth was boosted by expansions in both product categories. The credit card portfolio expanded sequentially, growing by 42% year-over-year to $15.1 billion. This growth was driven by the combined effect of onboarding new customers and increasing the share of wallet of existing customers across all segments. For yet another quarter, our personal loan portfolio was a highlight, increasing 88% year-over-year and reaching $4.5 billion. Following the consistent trends observed in previous quarters, our personal loan cohorts have continued to exhibit expected credit behaviors, which has enabled us to continue to scale originations.
Now let's move to the breakdown of interest-earning loans within our credit card portfolio. Interest-earning installment balances now account for 26% of our total credit card portfolio, up from 23% last quarter. This sequential growth was mainly underpinned by the successful expansion of our PIX and boletos financing products. As we previously mentioned, we believe that this type of financing offers an attractive risk-adjusted rate of return, allowing us to further expand the monetization of our credit card business, while also unlocking substantial value as we fulfill an important customer need.
This strategy is reinforced by the fact that our share of revolving receivables has not increased, representing 6% of our total receivables again this quarter. Delving into our personal loan business, our portfolio composed of both unsecured and secured loans remains aligned with our expectations for asset quality. Originations reached BRL 12.3 billion in the quarter with secured personal loans growing according to plan and originations reaching BRL 1.7 billion, almost doubling versus the prior quarter. This represents 14% of the total originated versus 10% in the previous quarter.
As discussed in the previous earnings call, we are very pleased to note significant progress in broadening our lending portfolio. We have introduced payroll loans for federal public servants and retirees, FGTS anticipation and investment-backed loans. Although still ramping up, this portfolio should contribute to the development of an even more resilient credit book in the years to come.
Following the same trend as last quarter, our credit yield was affected by the loan mix as secured personal loans have lower interest rates and increase in originations of these loans directly impact the average interest rate of our personal loan portfolio. This decrease in credit yield was only partially offset by a slight increase in the unsecured lending yield as a result of our continued risk expansions.
Now let's review the progress achieved on the funding front. It's important to remember that fourth quarters are seasonally strong in deposit inflows, while first quarters are seasonally weak, representing a historical drop of approximately 4.6%. While we noted an expected decrease in deposits in Brazil, the total for the quarter of our deposits base increased and reached $24.3 billion, representing a 53% year-over-year growth, mainly driven by Mexico, where we are experiencing significant growth in Cuenta Nu.
By the end of the first quarter of 2024, we achieved over $2 billion in deposits in Mexico, more than doubling when compared to last quarter. Similar to Brazil, this growth represents a very significant milestone towards our goal of developing one of the strongest local currency retail deposit franchise in the region, bolstering our ability to support our consumer finance operations across all of the geos where we operate. Our cost of deposits, defined as the ratio between the interest income paid to customers and the interbank rate of the respective markets, namely TIIE for Mexico and CDI for Brazil, was 84% of the interbank rate, very much in line with our expectations.
The increase in cost of deposits this quarter is directly linked to the growth of our franchise in Mexico. We believe this consistently low cost of deposits highlights our progress in harnessing the value of our liability franchise. Our loan-to-deposit ratio, or LDR, stood at 40% versus 34% in the previous quarters with deposit growth accelerating sequentially. We are very confident that there is still a lot of room for additional balance sheet optimization.
Net interest income, or NII, nearly doubled year-on-year, reaching another record high of $1.6 billion. This was driven by the growth of our credit card and lending portfolios, which collectively have propelled the expansion of our NII and of our net interest margins, or NIM, to new record highs. For the first quarter of 2024, we delivered a net interest margin of 19.5%, representing an increase of 1.2 percentage points compared to last quarter and a 4.5 percentage points in comparison to 1 year ago.
As we look ahead and irrespective of the direction of interest rates, we believe that the main lever for future NIMs should be the progression of the company's loan-to-deposit ratio. As our excess deposits are invested in public bonds, the remuneration of which is much lower than those of our credit products. Let's turn our attention to the last pillar of our overall strategy, maintaining a low cost-to-serve. We maintain our conviction that our platform is one of the most cost-effective in catering to customers within our operating markets with its low cost-to-serve standing as a significant competitive advantage.
That is the reason we aim at keeping it at or below $1 level for the foreseeable future. For yet another quarter, we were successful in achieving this goal with a cost-to-serve per active customer standing at $0.90. This figure currently remains unchanged on an FX-neutral basis when compared to a year ago, while our ARPAC, as mentioned earlier, increased by 30%, demonstrating the strong operating leverage of our business model. Our gross profit reached a new quarterly record high at approximately $1.2 billion, a 76% year-over-year increase.
As we mentioned during our last earnings call, we expected annualized gross margins to normalize to levels of 2023 as our investments in Mexico and Colombia are offset by the positive trends expected for Brazil. The sequential drop in gross profit margins in the first quarter was driven by 2 main factors: Number one, the seasonal drop in cards purchase volumes, which impacted interchange revenues when compared to the fourth quarter; and number two, the increase in growth, which drove credit loss allowance billed in the quarter. Yet, our gross profit margins reached 43.2% this quarter, an increase of 3 percentage points in comparison to 1 year ago.
One of the key elements of our strategy is achieving operating leverage. Our efficiency ratio stood at 32.1% during the first quarter of 2024, an improvement of almost 4 percentage points in relation to the last quarter of 2023 and almost 7 percentage points better than 1 year ago. Please recall that during the fourth quarter of 2023, our efficiency ratio was impacted by higher marketing expenses, mainly due to the phasing of this cost into the end of the year, together with higher cloud expenses, driven by seasonal increases in data usage in the quarter.
As we mentioned at the time, we believe that our efficiency ratio would come to normalize during the following quarters, as demonstrated during this first quarter of 2024. We continue to believe that this positions Nu as one of the most efficient financial services companies in the world. We expect to benefit from the full potential of our platform's operating leverage as we continue to grow our customer base, upsell and cross-sell products, launch new features and eventually achieve profitability in the new geos of Mexico and Colombia, which are still in their investment phases.
Let's now review the sustainable advantages across our 4 cost pillars: Number one, our cost to acquire was stable at $7, an amount we continue to believe to be one of the lowest among consumer fintechs and banks globally; number two, our cost-to-serve remained as expected at a low level, below $1, which we estimate to be approximately 85% lower than those of incumbent banks. Once again, we believe this level of cost to serve makes Nu one of the most efficient financial services companies in the world.
Number three, on cost of risk, again, we have effectively managed credit risk outperforming competitors on an apples-to-apples basis in terms of delinquency rates; and finally, number four, on the cost of funding, while significantly increasing deposit volumes, we were able to maintain our cost of funding at a competitive level of 84% of the blended interbank rates of Brazil and Mexico, thus closing the negative gap against incumbent banks and widening the positive gap over consumer fintechs.
And finally, moving to net income. We delivered another quarter of profitability with a net income of $379 million, increasing by 160% compared to the previous year. This strong and positive results serve as an evidence of the effectiveness of our strategy and business model. Additionally, adjusted net income reached $443 million in the quarter and 136% increase when compared to 1 year ago. While we are encouraged by the first quarter results, it's again important to emphasize our commitment to managing our business for long-term value creation. This may require undertaking material short-term investments aimed at optimizing our long-term opportunities.
Now I would like to hand the call over to Youssef, our President and Chief Operating Officer, who will walk you through the key highlights of our asset quality.