Alstom shares plunge 27% after cutting full-year guidance

A single-session drop of this size signals that the guidance cut landed as a genuine surprise rather than a widely anticipated reset, and the absence of specifics in the initial report leaves the market to price uncertainty rather than known damage. The read-across extends beyond Alstom to other capital-goods and infrastructure suppliers whose order books and cash conversion are similarly sensitive to project timing. Whether the company moves quickly to detail the drivers behind the revision, and whether peers face comparable pressures, is the open question.