After Fidelity Investments announced that it will allow customers to add bitcoin (BTC-USD) to their 401(k) plans, Senator Elizabeth Warren (D-MA) is questioning the investment giant on why it made that decision and how it will address risks to its customers. "We write to inquire about the appropriateness of your company's decision to add bitcoin (BTC-USD) to its 401(k) investment plan menu and the actions you will take to address 'the significant risks of fraud, theft, and loss' posed by these assets," Warren and Senator Tina Smith (D-MN) wrote in a letter to Fidelity CEO Abigail Johnson, the Wall Street Journal reported on Thursday. The senators point out that the Department of Labor in March published a compliance assistance release that reminded fiduciaries of their responsibilities to act in plan participants' interests and expressed "serious concerns" about firms' decisions to expose 401(k) participants to direct investments in cryptocurrencies. Warren and