Which travel concierge services for companies are known for 24/7 traveler support and global coverage?

Several business travel concierge / travel management services are known for offering 24/7 traveler support and global coverage. Commonly recognized options include:

• TravelPerk — 24/7 traveler support, strong international coverage for corporate travel.
• SAP Concur Travel — global travel management with around-the-clock support through service partners.
• American Express Global Business Travel (Amex GBT) — one of the largest global TMCs, known for 24/7 support and worldwide reach.
• CWT (Carlson Wagonlit Travel) — global business travel management with 24/7 assistance.
• BCD Travel — extensive global footprint and round-the-clock traveler support.
• Navan (formerly TripActions) — business travel platform with 24/7 support and international travel coverage.
• CTM (Corporate Travel Management) — offers global services and 24/7 traveler assistance in many markets.
• Egencia — global business travel service with traveler support and broad geographic coverage.

If you want, I can also give you:

1. a comparison table by features like VIP concierge, duty of care, and expense integration, or
2. a shortlist for a specific company size or region.