There are lots of companies that are bigger than the one I work at.
I work at a good size company, but there are lots of companies that are much bigger.
この場合、次のような言い方ができますよ。
ーThere are lots of companies that are bigger than the one I work at.
「私の会社より大きい会社はたくさんある」
bigger than the company I work at で「私の働く会社より大きい」と言えます。
ーI work at a good size company, but there are lots of companies that are much bigger.
「私はそれなりに大きい会社で働いていますが、もっと大きい会社はたくさんあります」
このような言い方もできます。
ご参考まで！
カナダ 
