SANTA ROSA -- American AgCredit returned the largest member dividend in its history in 2012, the agricultural cooperative’s first year of positive loan growth since 2009, the lender reported today.

That dividend, totaling $45 million, effectively reduced the interest rate of borrowers’ loans by 1 percent, according to the lender’s year-end report.

Loan volume grew 32.5 percent to $5.8 billion for the year. Part of that increase was due to the acquisition of Colorado-based Farm Credit Services of the Mountain Plains in early 2012, which propelled American AgCredit to its current position as the sixth-largest agriculture lender in the country.

Costs related to that acquisition reduced net income 40.6 percent to $107.3 million from 2011. Without those costs, that income would be equivalent to a 15.7 percent increase, according to the report.

Total assets in 2012 were $6.2 billion. American AgCredit is building a new headquarters in Santa Rosa. Executives said the facility will serve its plans to expand offerings in crop insurance and other products in the coming years.