Out of that group, CU Direct's 92 credit union shareholders had $203.8 billion in assets and 14.1 million members on Sept. 30.

CU Direct signed new agreements with 71 credit unions in 2017.  At year's end, its agreements covered 1,117 credit unions serving 47.8 million members for its technology products, including CUDL, Lending 360, Lending Insights, AutoSMART and OnSpot Financing.

Credit unions funded 1.8 million loans through CU Direct's Lending 360 and CUDL lending platform, generating a record $39 billion in credit union auto loans in 2017, up from $32 billion in 2016.

CU Direct credit union partners, as an aggregate, became the largest auto lender in the nation in 2017, experiencing 16.2% loan growth, the second-highest loan origination growth rate among the top 10 lenders in the nation according to data from AutoCount.

CU Direct said its credit unions have doubled their auto loans since 2013.

While CU Direct cites originations, that data is missing from NCUA call report data for cars or indirect loans. Instead, NCUA makes available portfolio balances. While runoff is relatively fast for auto loans, the data still obscures recent trends.

NCUA also reports indirect lending as a whole, which is primarily automobiles, but also includes everything from boats to hot tubs. NCUA data shows total indirect loans also doubled from 2013 to 2017. As of Sept. 30, 2017 credit unions had $189.5 billion indirect loans on the books, and $326.3 in total auto loans.

CUNA estimates the year-end auto loan balance was $344.5 billion, which based on Fed data gives the credit union movement a 30% share of the U.S. auto lending market, up from about 28% at the end of 2016.

NCUA data shows CU Direct's 92 credit union shareholders increased their car loan portfolios by 15% from Sept. 30, 2016 to Sept. 30, 2017. New car loans rose 19% to $23.2 billion, while used car loans rose 13% to $30.2 billion. Indirect loans rose 19% to $38.4 billion and accounted for 27% of total loans.

The other 1,843 indirect lenders had nearly the same growth rate and loan allocations. Their new car loans rose 16% to $86.1 billion, used car loans rose 13% to $137 billion, indirect loans rose 21% to $151.7 billion and total loans rose 12% to $597.2 billion.

Credit unions that didn't make indirect loans had slower loan growth and car lending represented only 25% of total loans. New car loans rose 9% to $19.7 billion, used car loans rose 8% to 32.5 billion and total loans grew 8% to $205.2 billion.

However, margins are lower on indirect auto loans. Among the 10 largest direct auto lenders, returns on average assets were 1.21% for the 12 months ending Sept. 30, up 8 basis points from a year earlier. Among the top 10 indirect lenders, ROA was 0.97%, down 3 basis points. ROA for all credit unions was 0.77%, up 2 basis points.