We do have a legitimate and strong regulatory interest in how stablecoins are constructed and managed, particularly with respect to financial stability concerns: the pool of assets that acts as the anchor for a stablecoin’s value could—if use of the stablecoin became widespread enough— create stability risk if it is invested in multiple currency denominations; if it is a fractional rather than full reserve; if the stablecoin holder does not have a clear claim on the underlying asset; or if the pool is invested in instruments other than the most liquid possible, principally central bank reserves and short-term sovereign bonds.
All of these factors create “run risk” —the possibility that some triggering event could cause a large number of stablecoin holders to exchange their coins all at once for other assets and that the stablecoin system would not be able to meet such demands while maintaining a reasonably stable value.