Grab, a popular ride-hailing app in the Philippines, came under scrutiny for its opaque surge pricing algorithm. 

An investigation by the Philippine Center for Investigative Journalism (PCIJ) revealed that GrabCar rides always include surge fees, regardless of the time or day, resulting in fares being consistently above the minimum fare estimated by Grab's own fare check tool.

The investigators also found that high fares did not always correlate with shorter waiting times, contradicting Grab's advertised purpose of surge pricing, and the algorithm's behaviour often differed from Grab's public explanations of how it works.

Grab refuses to reveal the actual process for calculating fares, resulting in critics accusing the company of profiteering and opacity. 

The company has been regularly under scrutiny for overpricing, ride cancellations and other issues since its acquisition of Uber's business across South-east Asia.

The investigation highlights concerns about algorithmic transparency and fairness in ride-hailing services. It also raises questions about the effectiveness of surge pricing in improving service quality, as long wait times persisted even during high-fare periods.