Who makes Mack trucks?

Mack trucks are produced by the Volvo Group. The Volvo Group is a publicly-held company headquartered in Gothenburg, Sweden. Volvo Shares are listed on OMX Nordic Exchange Stockholm and are traded OTC in the US.

http://www.macktrucks.com/default.aspx?pageid=1

That took me less than 3 seconds to find on google. Next time use google before asking a question and stop being lazy.