Prosperity bank is indeed insured by the FDIC, I quote from
their site: "Prosperity Bank has been FDIC insured since September
13, 1949. It was established on September 13, 1949. Its main office
(headquarters) is located at: 1301 North Mechanic Street El Campo,
Texas 77437 County of Wharton Prosperity Bank has 186 Domestic
Branches (Offices) located in 1 state(s) and 0 Foreign Offices.
(Check to locate Branches (Offices) by state.) Prosperity Bank's
reported (or primary) website: http://www.prosperitybanktx.com:80/"
You can find the page about them here:
http://www2.fdic.gov/idasp/frmBankAtGlance.asp?inCert1=16835&Status=Y&InstName=PROSPERITY+BANK&Act_Num=&UNQNUM=10936