The Obama administration scrambled to resolve its remaining crisis-era megabank mortgage cases, striking multibillion-dollar settlements with Deutsche Bank AG and Credit Suisse Group AG over toxic securities while separately filing a lawsuit against Barclays PLC alleging more than $30 billion in fraud-tainted sales.

U.S. authorities settled with Deutsche Bank for $7.2 billion Thursday. Early Friday, Credit Suisse said it had agreed to pay about $5.3 billion to close the matter.

Deutsche...