Nu Holdings looks poised to keep delivering wins for long-term investors. Meanwhile, Nu Holdings (NU -0.92%) stock has managed to soar far higher than either index -- up 56% -- across this year's trading. Nu Holdings still has what it takes to be a big winnerIn the second quarter, Nu Holdings posted year-over-year sales growth of 42% on a currency-adjusted basis. The business added 4.1 million new customers in the period -- good enough to deliver year-over-year growth of 17%. In between a strong sales growth outlook and the potential for substantial profit-margin improvements, Nu Holdings is a stock that looks poised to significantly outperform the financials sector.