GMR Airports Infrastructure on Tuesday announced acquiring an 8.4 per cent stake in WAISL, which provides digital infrastructure services at airports, as the company looks to strengthen its presence in airport-related businesses. The company has entered into an agreement to buy 4,60,000 shares or an 8.4 per cent stake of WAISL from Utthishta Virat Fund for Rs 56.66 crore, according to a regulatory filing on Tuesday.