M&A activity in the global automotive sector plunged in the third quarter, PricewaterhouseCoopers LLP said in a report, citing fewer big-ticket deals.

Mergers and acquisitions around the world have sunk to three-year lows, accelerated by trade tensions and growing economic uncertainty.

The size of automotive deals in the quarter declined to $7 billion in the quarter from $18 billion a year earlier, PwC said.

The industry's M&A volumes tumbled to a seven-quarter low, falling 16.5% to 197 deals, according to the report.

Hyundai Motor Co's $1.6 billion joint venture with U.S.-based Aptiv Plc was the biggest deal in terms of value in the quarter.

The industry deal volume has fallen by 24% to 604 deals so far this year, while the deal size has halved to $31 billion, the auditing firm said.

German auto parts maker ZF Friedrichshafen AG's $7.4 billion deal to buy WABCO Holdings in March is the biggest automotive deal so far in 2019.

Although technology was the main driver of M&A activity in the third quarter, it might not be so going forward with the sector facing leaner times, PwC said.

"Deal makers are letting the dust settle and are focusing on the development of their previous bets," PwC said.

However, with both strategic and financial investors remaining in a position to buy, there is reason to believe M&A could bounce back if more attractive assets become available, PwC said.