1. WordPress.com - Hosted SaaS for building websites. Very cheap to run, includes ads on free sites, and they sell users upgrades like custom domains or removing ads from their sites.
2. Jetpack - Services for self-hosted WordPress sites, like backups, social media integration, image CDN, antispam - mostly paid services, again very cheap to run.
3. WooCommerce - Open source ecommerce service. They sell add-ons like payment gateways, and have their own with a percentage fee of each transaction.
4. WPVIP - Enterprise and high-scale hosting service. Expensive ($25k/yr+) but worth it for large companies who run their business off it, like newsrooms and marketing sites.
To my knowledge, they're each independently profitable. Automattic also has a lot of additional smaller services which support these, and various Other Bets.
(I don't work at Automattic, but have many friends there.)