Savings institutions reported a total of $200.9 billion of residential MBS in their retained portfolios at the end of the first quarter of 2011, up marginally from the end of the previous year. But the heart of the industry – firms regulated by the Office of Thrift Supervision – actually posted a small decline in their MBS holdings during the period. The OTS itself is being phased out as a separate federal regulator, although the savings association charter will continue under the supervision of a dedicated unit in the Office of the Comptroller of the Currency. OTS-regulated thrifts held $157.6 billion of MBS in their portfolios at the end of... [Includes two data charts]