A lawsuit has been filed against Google seeking compensation for lost revenue of £3.4 billion ($4.2 billion).

The claim, made by ex-Guardian technology editor Charles Arthur, alleges that Google illegally used its dominant position in online advertising to reduce the amount of money publishers could make from them.

Google stated that it would vigorously oppose the “speculative and opportunistic” action.

It is the second such lawsuit, following a similar one filed in November.

Claudio Pollack, a former Ofcom director, is suing the tech giant for up to £13.6 billion in damages.

The cases involve advertising technology, or adtech, which determines which online advertisements consumers will see, how much they will cost, and how much publishers will earn in a fraction of a second.

Many websites rely heavily on online display advertising as their primary source of revenue.

Google is being sued for €25 billion in the United Kingdom and the European Union.
The Competition and Markets Authority (CMA) in the United Kingdom is also looking into Google’s dominance in advertising technology.