It was a hot year for M&A in the U.S., and supply chain deals became commonplace as companies worked to gain greater control over operations.

The Federal Trade Commission received more than 2,000 merger filings in the first seven months of 2021, an "astounding" jump in activity representing a 138% YoY growth in deals, according to an FTC executive.

Many deals came as shippers sought to integrate vertically, acquiring suppliers or technology that would make them more competitive. Software providers acquired peers and rivals to expand their services. And one set of carriers even engaged in a monthslong bidding war as they raced to create a railroad that spans from Canada to Mexico.

As the year comes to an end, we look back at 10 deals that showcase the M&A trends of 2021.