Air, hotel, and rental car bookings represent only 60 to 70 per cent of total business travel expenses, and companies need to exert greater control over employees’ other spending, according to experts at Travel Leaders Group’s ViewFrom36K consultancy.

“Companies’ travel and expense data is typically their second or third-largest expense,” said Gabe Rizzi, president of Travel Leaders Corporate. “If they don’t get full visibility into what employees book as well as what they actually spend, companies won’t understand the true cost of a trip and they won’t have the right insights to negotiate.”

Corporate credit cards offer the best opportunity for tracking such spending, as well as whether employees are booking flights or rooms outside of agreements with airlines and hotels — deals that can save companies anywhere from 15 to 25 per cent. “It’s critical to reduce your out-of-program spend to ensure you’re getting the lowest negotiated rates,” noted Rizzi.

Rizzi also advised companies to scrutinise expense reports to determine the true cost of business travel, including out-of-pocket spending.

Accounting for and controlling spending on meals, ride sharing, and other non-bookable business travel expenses is especially important as the overall cost of travel is projected to rise, according to Rizzi.