The younger brother of George IV, William IV was also the last King of Hanover. Known primarily for officially abolishing slavery and the introduction of the Reform Bill. High grade WIlliam IV coins of all denominations are difficult to come by. In addition to his short reign coinage was very limited, for example Pennies and Halfpennies were minted only in 1831,1834 and 1837. William Wyon was once again primarily responsible for the engraving.
Coins of William IV tend to be a bit on the expensive side due to lack of available specimens, particularly in higher grades. During his reign coins were only struck as follows, and none of them are common:
Farthings - 1831, 1834, 1835, 1836, 1837
Halfpennies & Pennies - 1831, 1834, 1837
Silver & Gold - 1831, 1834, 1835, 1836, 1837
1834 Farthing, NGC MS 64 BN.
1837 Halfpenny, NGC MS 63 BN.
1834 Penny, NGC MS 65BN.
1834 Sixpence, NGC MS 65.
1836 Shilling, NGC MS 64.
1831 Halfpenny Proof, NGC PF 65BN.