Three heirs to the Walmart fortune have given away hundreds of millions of dollars worth of the retailer’s shares to a family trust that finances its philanthropy.

According to regulatory filings on New Year’s Eve, Alice Walton, the daughter of Walmart founder Sam Walton, gave away 3.7 million of her Wal-Mart Stores wmt shares on December 28, a gift worth about $225 million based on that day’s closing price, to Walton Family Holdings Trust.

Rob Walton, until last year the retailer’s chairman, and his brother, Jim, each gave away 1.5 million shares, too, bringing the value of last week’s transaction to $407 million. (That it is an eye-popping amount until you consider that the Walton family’s stake in the company, just about 50%, is worth about $95 billion as of now.)

The giveaways are part of a previously announced effort by the Walton family to pare its stake in the world’s largest retailer by giving billions of dollars worth of shares to a trust that will sell them over time.

A series of share buybacks by Wal-Mart Stores, which owns Walmart in the U.S. and abroad as well as Sam’s Club, in recent years had lifted the Waltons’ ownership to about 50%, a threshold the company said last year the family did not want to exceed, citing corporate governance practices.

Walton Enterprises, the holding company owned by America’s richest family, said in April that it would gradually distribute approximately 6% of Wal-Mart’s outstanding shares – or some 193.5 million shares, worth $15.6 billion at the time – to a newly formed entity, the Walton Family Holdings Trust. (Wal-Mart shares have fallen 24% since then on investor concerns about its ability to compete with amzn )

Alice, Jim and Rob Walton each have a net worth of more than $30 billion, according to Forbes’ 2015 list of wealthiest people.