Saying that having a stable corporate credit union system is "essential to maintain liquidity and investment services," and provide payment systems, the NCUA has sent a six-page letter to credit unions explaining the rationale behind last week's approval by the NCUA Board to levy a 13.4 basis points assessment for the Temporary Corporate Credit Union Stabilization Fund.

NCUA Chairman Debbie Matz said the decision on whether to levy the assessment and its size was based on three factors: The fund's liquidity needs; the "downward pressure on natural credit union earnings;" and the long-term consequences if the agency forgoes the assessment this year, because this "would have required even larger assessments to be levied over the next five years."

The assessment, which the agency expects to raise $1 billion, is needed to make a Sept. 30 repayment of $1.5 billion borrowed from the Treasury Department. The remainder will be a reduction in the liquidity assistance provided to the corporate system. The assessments, which are based on insured shares as of March 31, are due in mid-August.