Manila Water suffers from 3.5% loss within this period, the biggest one reported since June 24. In parallel, the Philippine Stock Exchange also went down by 0.2%.

Stock prices for the said water regulator were affected negatively by news of how the Metropolitan Waterworks and Sewerage System Regulatory Office revoked a rule that has been in place for 9 years and as a result, income tax obligations of MWC were passed on to its consumers. For the period 2008 to 2012, a total of 352 million dollars were allegedly passed on to consumers' utility bills.

The owner of Maynilad Water, Metro Pacific Investments Corp or MPI, also saw its share prices negatively affected by this discovery. Uncertainty is anticipated to continue, analysts say. If the government will continue to not allow tax as a legitimate expense, MWC's value will continue to plummet down.