These patents remained on all Monopoly games until 1941 when the Magie patent expired and was removed.
The phrase A PARKER TRADING GAME was added to the box tops in 1937.
Their patent was issued on Dec 31, 1935, patent number 2,026,082.
The new patent was added to the labels and games produced from 1936 - 1941 included both patents printed on the labels.
It is estimated that over 100,000 'Patent Pending' games could have been made.
No Number 9 White Box games are known with the PATENT PENDING statement on the box. After purchasing rights for Monopoly from Charles Darrow, research discovered another game very similar to Monopoly had been patented in 1924 by Elizabeth Magie.