China's military says it stationed readiness patrols over the Scarborough Shoal's sea and airspace

The established pattern is that such declarations follow or anticipate a rival transit, exercise, or coast guard encounter, and the sequence that matters is whether rhetoric is followed by physical interdiction of Philippine or allied vessels, since that is the step that has historically drawn in treaty commitments and shifted the risk premium. The channel to markets in comparable episodes has run through regional freight and insurance costs and, at the margin, the Philippine peso and regional equity peers, rather than through broader risk assets. The distinction worth drawing is between air and sea patrols announced for domestic and diplomatic consumption and an actual change in the rules of engagement on the water; the former has been common, the latter rare. The follow-ons to note are any Philippine or US response, coast guard incident reports, and whether the announcement coincides with a wider diplomatic track, since patrol rhetoric has often preceded de-escalatory contact as much as confrontation.