Congressional Democrats are strongly opposing a US Department of Labor proposal that would allow 401(k) investments to include cryptocurrency, private credit and private equity assets, arguing the change will expose workers to riskier and more complex investments.

In a letter shared exclusively with the Guardian, Senator Bernie Sanders, Senator Elizabeth Warren and House education and workforce committee ranking member Bobby Scott of Virginia, argued the rule would expose an estimated $14.2tn of 401(k) retirement savings to volatile assets and would probably not withstand a challenge in court.

“This would strip long-held investor protections from retirement savers and encourage the use of more risky, complex, and expensive…