It's been a pretty successful year for Alphabet, parent company of Google.

The stock is up more than 34 percent this year, and its market cap has swelled to more than $736 billion, according to data from FactSet. Its biggest cash cow is still .

But as Google's business grew, so did the number of companies expressing fear of Google.

The financial search engine AlphaSense tracks which companies see Google as a threat by scouring the year's earnings, event transcripts, releases and major SEC filings for mentions of the search giant that appear within 15 words of synonyms for competition, risk, threat and similar words. It registered 262 hits this year, up from 236 last year.

So, which companies talked fretfully — or fielded anxious queries from investors and analysts — about Google this year?

Foremost was the advertising agency WPP, which had nine anxiety-fueled Google references in 2017, up from seven in 2016.

Prominently, one of those came during the company's third-quarter earnings when its own presentation asked the question: "Are Google and Facebook eating our lunch?"

WPP saw pretty flat revenue in Q3 and North American revenue growth declined, though CEO Martin Sorrell has said that low growth is the "new normal" and that Google and Facebook aren't actually disrupting the traditional ad agency model. (The fear here is that even though Google and Facebook get the bulk of WPP's ad spend, they also encourage its clients to use their tools directly versus going through an agency middleman.)

Criteo, a French ad-tech company, also saw an increase from 4 to 5 Google-related references this year. One question came during a Stifel Technology Conference in June, where an analyst asked about how the company differentiates its products from Google's.

Although the two companies have a significant partnership, they also have a competing product. However, Criteo CFO Benoit Fouilland said Google tends to go after the "long-tail" versus the top markets that his company chases.

"[T]here are certain obstacles as well for Google to be able to develop the type of close relationship we've developed with large retailers," answered Fouilland. "Many of them would be very reluctant to share the type of data they share with us with Google. So that's probably one of the reasons why we don't face Google that much even if they have definitely a competing product."

On the travel-related side of things, Expedia had six Google mentions, according to AlphaSense.

In July, Dara Khosrowshahi (then Expedia CEO, now running Uber) called Google an "existential threat" to Expedia that was competing for "the consumers' hearts and minds when they have a travel question" in an interview with The Financial Times.

As Google has fleshed out its flight and hotel comparison tools, Trivago is feeling the heat, too.