The phrase "biggest producer" refers to the entity or country that creates or manufactures the largest amount of something compared to others. It suggests that this entity or country is ahead of others in terms of quantity or output. Full definition
For us, that would have been using the second biggest producer of marketing products. (inc.com)
For example, we wanted a really big producer in the area to come join us, but we didn't like his overall demeanor after several interviews. (rismedia.com)
We hear that it empowers women, but even porn's biggest producers don't want their daughters in the business. (futureofpersonalhealth.com)