The volume of credit unions' credit card portfolio sales slowed during the second quarter ended June 30 compared with the same period a year earlier, AssetExchange, a credit card advisory and brokerage firm for credit unions, said in a report released this week. The Portland, Ore.-based firm analyzed National Credit Union Administration data from 2,100 credit unions with credit card portfolios containing outstanding receivables of at least $1 million. Credit unions sold portfolios representing a total of $4.5 million in combined outstanding receivables during the quarter, a 77.5% decline from $20 million during the same period last year. Outstanding receivables within all credit card portfolios held by credit unions reached $32 billion at the end of June, up 6.3% from $30.1 billion a year earlier. Total card accounts grew 2.2%, to 12.3 million from 12.03 million. The ratio of credit card receivables as a percentage of total assets declined to 4.57% during the quarter, down from 4.8% a year ago. Credit card penetration among credit-union customers remained flat at 18%.