The captives' involvement has proved crucial to Mexico's finally joining the ranks of more developed car markets in which credit is plentiful and long-term loans come with reasonable interest rates.
A record number of sales financed through car loans last year -- nearly 838,000, up 23 percent from 2014 -- led to record domestic sales of 1.35 million vehicles. This year is on pace to set a new lending record, with new-vehicle sales up 18 percent for the first six months to historic highs and automaker lending climbing to 70 percent of car loans this year through May.
Mexico's biggest new-car lenders are also the country's biggest new-car sellers: Nissan, General Motors and Volkswagen. Together, they issued about half of all auto loans last year, according to the dealers association.
"If we analyze the volume handled by automaker financing in the auto sector, it's very important," said Francisco Garza, GM's vice president of sales for Mexico, Central America and the Caribbean. "GM Financial is our financing arm, and last year it grew much more than the auto industry as a whole."
Industry officials say there's more that can be done to get financing into the hands of more people.
While Mexican inflation hit a record low of 2.1 percent last year, the average rate for a car loan was about 12 percent, according to the dealers association. Promotional rates do go lower, but there still is a significant spread over inflation.
Garza said the gap is due partially to Mexican laws that make it difficult for lenders to repossess cars from owners who have fallen behind in their payments.
"There are still some changes needed to the legal framework of the financial system," he said. "In the U.S., you can get a "repo' the day after the buyer has fallen 60 days behind." In Mexico, by contrast, repossession requires a civil suit, usually met with a countersuit and months of legal fees.
Luckily for lenders, nonperforming loans are only 1.5 percent of the total, according to Guillermo Rosales, co-director of the auto dealers association. That is one of several indicators pointing to continued growth in the auto-financing sector, he said.
After Mexico's 1995 economic crisis, local banks were broke, but the U.S. financial system had capital to lend, Rosales said. Thus began a stepped-up presence by automakers' financial arms.
"When the Mexican financial system collapsed in 1995, what saved vehicle sales and allowed them to recover is precisely the participation of specialized financing by the brands," he said.
Over time, those operations have consolidated and matured into the market we see today, with a growing share of auto purchases being financed. And more auto loans are stretching out to 60 months, making car buying more affordable to some segments of the population.
Mayra Gonzalez, the new president of Nissan Mexicana, said Nissan is creating new financing products for underserved segments, since only about half of the population has access to credit.
Nissan's Subete program offers credit to buyers who are self-employed or otherwise cannot present proof of a steady paycheck. The Sin Fronteras program allows Mexican migrants in the U.S. to qualify for credit and purchase a car back home in Mexico for their families. And, Gonzalez said, Nissan is working on a financing product aimed at students.
"We have found new market segments," Gonzalez said. "If you open the possibility of credit to more people, that obviously increases sales."