The Walmart heir everyone believed was one of the richest women in America is actually poorer than people thought

Until last month, Christy Walton, Walmart heir John T. Walton's widow, was regarded as the richest woman in America.

In fact, Christy's fortune is $27 billion less than widely believed, according to Bloomberg.

When John T. Walton died, it was assumed he passed his fortune on to his widow. Instead, recently unsealed court documents reveal he gave half of his then-$17 billion to charitable trusts and a third to his only child, Lukas Walton.

That leaves 17% to Christy. As a result, the estimated value of her fortune has dropped to about $5 billion from $32 billion.

While Christy's position amongst the richest of the rich drops with the news, the rank of her son, Lukas, has shot up. Now, he is the 103rd-richest person in the world, worth about $11 billion, and, according to the Bloomberg Billionaire Index, as much as $25 billion if certain trusts are included.