U.S. companies looking to grow through acquisition have been searching fervently in recent years for overseas deals that involve a tax-saving process known as an inversion. These deals enable U.S. multinational companies to lower their tax bills by combining with a company located in a country with a lower tax rate, then reorganizing in that country to take advantage of that rate.

U.S. companies looking to grow through acquisition have been searching fervently in recent years for overseas deals that involve a tax-saving process known as an inversion. These deals enable U.S. multinational companies to lower their tax bills by combining with a company located in a country with a lower tax rate, then reorganizing in that country to take advantage of that rate.

The data firm Dealogic says 27 acquisitions involving an inversion with a U.S. company have been proposed or completed since 2011. Those deals total more than $420 billion in value, with about $344 billion in deals being proposed since the start of 2014. Here are some of the biggest excluding debt, with the year in which they were announced.

2015: Pfizer Inc. buys Allergan Plc for $146.5 billion (pending).

2014: Medtronic Inc. buys Covidien Plc for $49.66 billion (completed).

2013: Liberty Global Inc. buys Virgin Media Inc. for $17.03 billion (completed).

2012: Eaton Corp. buys Cooper Industries Plc for $13.14 billion (completed).

2014: Burger King Worldwide Inc. buys Tim Hortons Inc. for $12.01 billion (completed).

Source: Dealogic