The news: US spending on luxury brands fell 6% YoY in September, the third straight monthly decline after sales fell 4% in both July and August, per a new Citi report based on the company’s credit card data.

The slowdown is significant given the US’ outsize importance to the luxury industry. The US is expected to account for 31% of global luxury spending this year, well ahead of Europe’s 22% and China’s 18%, per a Morningstar analysis shared with Bloomberg. Morningstar expects US consumers to remain the largest source of luxury sales through 2035.

That makes a potential US slowdown particularly consequential as luxury brands navigate weakness elsewhere, including China—where we expect personal luxury sales to grow 3.5% YoY this year—as well as broader economic uncertainty and geopolitical conflicts.