London-based fintech firm Trading.co.uk is launching an app that will generate trading alerts for shares based on comments made on social media by Donald Trump.

Keeping one eye on the U.S. President-elect’s personal Twitter feed has become a regular pastime for the fund managers and traders who invest billions of dollars daily on world stock, currency and commodity markets.

Trump knocked several billion off the value of pharmaceutical stocks a week ago by saying they were “getting away with murder” with their prices. Comments last week on China moved the dollar and a pair of December tweets sent the share prices of Lockheed Martin and Boeing spiralling lower.

That plays to the growing group of technology startups that use computing power to process millions of messages posted online every day and generate early warnings on when shares are likely to move.

Trading.co.uk chief Gareth Mann said the Trump signal generator used artificial intelligence technology to differentiate between tweets or other messages that, for example, just mention Boeing and those liable to move markets.

“It is impact analysis,” he said. “We can let you know when Trump tweets. We can let you know when he mentions a particular stock, or when he mentions a stock and a country. But if he just says he’s riding on a Boeing 747 the system will do nothing.”