Complex sentence: This dominance over the paper supply put Penguin in an especially strong position after the war as rationing continued, many of its competitors were forced to concede paperback reprint rights to Penguin for this reason as well as the popular prestige the company enjoyed.
Split into simpler sentences: This dominance over the paper supply put Penguin in an especially strong position after the war as rationing continued. Many of its competitors were forced to concede paperback reprint rights to Penguin for this reason as well as the popular prestige the company enjoyed.