SmartAsset and Yahoo Finance LLC may earn commission or revenue through links in the content below. Converting money from a tax-deferred retirement account to a Roth IRA can cause Medicare premiums for Part B and Part D to increase – in some cases dramatically – because Medicare premiums are tied to income brackets. When retirement funds are transferred to a Roth account, the converted amount is treated as income. If the amount converted is large enough, it can potentially push the Medicare recipient int ...