If you’re rooting around for vulnerabilities in PayPal Holdings Inc.‘s (NASDAQ: PYPL) business model, you’ll have to peer closely. So far this year, the company’s focus on a few distinct themes, including higher mobile-transaction volume, additional payment partnerships, and ease of customer use, has fortified existing competitive advantages. PayPal reported impressive results across both its financial statements and key internal metrics in its third-quarter 2017 earnings filing, released Thursday after the closing bell.