Finding the largest pocket knife around maybe a difficult thing to do but if you are looking for a knife with all the tools then the Wenger Giant is undoubtedly the largest one out there.
The Wenger Giant is the world’s largest Swiss Army knife, packing 141 functions into 87 implements. At 9” wide and 32 ounces, this dang thing is so big that you could use it as a pretty nice anchor for your boat, if it didn’t list at $2100 (street price $1300). To put the weight into perspective, an everyday Swiss Army knife weighs 1.6 ounces!
If you are looking at records then the Guiness Book of Records say “The world’s largest pocket knife measures 6.02 m (17 ft 33 in) when open and has a steel blade 2.46 m (8 ft 1 in) long. It was designed and made by Garima Foundation and Pankaj Ojha (all India) and was presented at the Pink Square Mall, Jaipur, India, on 21 December 2010.”