SANTA MONICA, Calif. — Third-party lead provider TrueCar added 840 net franchise and independent dealers in the first quarter of 2015, the biggest-ever volume gain in company history.

TrueCar's Certified Dealer network totaled a best ever 10,680 franchise and independent dealer partners at the end of the quarter, up 38% from a year ago, officials said. Active franchise dealers increased by 607 — the most for a single quarter — while the number of active independent dealers grew by 233. There were a total of 9,108 active franchise dealers as of March 31, while independent dealers totaled 1,572. Both figures are also record highs for TrueCar.

"This all-time record expansion is getting us closer to optimal dealer coverage across the U.S.," said Scott Painter, TrueCar's chief executive officer and founder. "Growing the TrueCar Certified Dealer network allows us to satisfy more consumers, more frequently in more places than ever."

With its cost-per-action business model, TrueCar isn't focused on signing up every dealer across the U.S. Instead, the company focuses primarily on dealer geographic coverage based on brands. TrueCar drives in-market car buyers to member dealers and asks dealer partners to pay for successful sales. As a result, the company's success is tied directly to its dealer partners selling more cars, officials said. TrueCar intends to continue adding dealer partners in geographic markets where it is underrepresented by certain brands.

"We appreciate our dealer partners' support and are pleased with the record level of dealer interest in TrueCar," Painter said. "Notwithstanding our growth in recent years, we're still in the early stages of building a national, consumer-facing brand. As a result, we look forward to helping our thousands of dealer partners nationwide be even more successful by sending increasing numbers of in-market car buyers to their dealerships."