Domestic automakers increased their certified pre-owned sales by more than 14 percent in July, and one of the Big 3 had its strongest CPO month of all time.

According to Autodata Corp., Fiat Chrysler Automobiles had its best month ever for certified sales.

Including the Fiat brand, FCA US had 16,710 CPO sales in July, a 31.4-percent increase from July 2014, Autodata said.

Without Fiat, it had 16,622 CPO sales, a 31.7-percent gain.

Year-to-date through July, FCA is at 107,359 certified sales without Fiat (up 29.9 percent) and 107,863 with Fiat (up 30.1 percent).

The previous best-ever month for FCA occured in May, when it sold 16,579 CPO units without Fiat and 16,661 units with Fiat included. 

Domestics, as a whole, moved 78,993 certified vehicles in July, beating year-ago figures by 14.1 percent. Through seven months, they have sold 552,437 units (up 18.3 percent).

The CPO sales at Ford totaled 25,166 units in July for a 9.4-percent increase, with year-to-date sales reaching 170,814 units (up 10.2 percent).

At General Motors, certified sales for the Buick, Chevrolet, GMC, Pontiac and Saturn brands were at 35,032 units for July (up 10.0 percent), with yearly sales at 259,324 (up 19.1 percent).

Cadillac posted 2,173 CPO sales in July (up 23.5 percent) and its year-to-date sales reached 14,940 units (up 25.8 percent).