The world's most capital-rich country exported labor-intensive goods

Trade theory predicted capital-abundant countries export capital-intensive goods and import labor-intensive ones. In 1953, economist Wassily Leontief tested this on US trade data and found the reverse: American exports were more labor-intensive than its imports, despite the US having the highest capital per worker on Earth. The finding baffled economists for years and pushed trade theory beyond simple factor endowments.

— Wassily Leontief, Domestic Production and Foreign Trade: The American Capital Position Re-Examined — Proceedings of the American Philosophical Society, 1953