Warren, who has said she's considering a run for president in 2020, wrote to five investment firms that had advocated for a liquidation of Toys "R" Us assets and asked them to consider supporting a severance fund.

Two of the company's owners, Bain Capital and KKR, have discussed setting up such a fund, according to sources familiar with the discussions. The company's third owner, Vornado Reality Trust, also received a letter from Warren about the issue.