The partnerships between Yahoo and Mozilla Firefox and tension with Apple appears to have shaken Google’s dominance of the US search market.

In the biggest dip since 2009, the internet giant’s market share dropped to 75.2% last month from 79.3% in December last year, according to reports from analytics firm StatCounter.

Meanwhile Yahoo’s share of the search market increased from 7.4% to 10.4%, which Statcounter attributes to the finalisation of a five-year deal with Mozilla in November, replacing Google as the default search engine in the US for Firefox 34.

Mozilla’s switch to Yahoo brings an end to a ten-year partnership between Google and the web browser.

“The move by Mozilla has had a definite impact on US search,” said StatCounter chief executive officer Aodhan Cullen. “The question now is whether Firefox users switch back to Google.”

Exciting partnership

The deal has been a positive move for Yahoo CEO Marissa Mayer, who announced she was thrilled by the partnership.

“I’m also excited about the long-term framework we developed with Mozilla for future product integrations and expansion into international markets,” she added.

Furthermore, with the deal with Google Search and Apple expiring this year, and tension between the two rising, many are left wondering whether Apple will keep Google as the default browser for Safari on iOS.

Nevertheless, Google undoubtedly remains the leader in the search market, with 37% of Americans using Google Chrome. Firefox lags behind, used by just 12% of browsers in the US.