InterContinental Hotels Group plc, informally InterContinental Hotels or IHG, is a British multinational hotels company headquartered in Denham, Buckinghamshire. IHG has nearly 800,000 guest rooms and more than 5,300 hotels across nearly 100 countries. IHG has a broad portfolio of brands, including Candlewood Suites, Crowne Plaza, Even Hotels, Holiday Inn, Holiday Inn Express, Hotel Indigo, Hualuxe, InterContinental, Kimpton Hotels and Resorts and Staybridge Suites. Additionally, in March 2018, IHG announced that it has agreed to buy a 51 % majority stake in Regent Hotels for $39 million and hopes to expand the brand's footprints to 40 hotels from the current six hotels.

Based on this passage, holiday inn express is part of what chain? Let's think fast. Stream of consciousness:
The relevant sentence in the passage is: IHG has a broad portfolio of brands, including Candlewood Suites, Crowne Plaza, Even Hotels, Holiday Inn, Holiday Inn Express, Hotel Indigo, Hualuxe, InterContinental, Kimpton Hotels and Resorts and Staybridge Suites. So the final answer is InterContinental Hotels Group plc.