Century Bancorp in Medford posted an 8.1 percent increase in net income during the third quarter this year, recording $6.2 million for the period ended Sept. 30, compared with $5.7 million a year ago.

Net income for the nine-month period ended Sept. 30 ticked up 5 percent to $17 million, over $16.2 million in the comparable period last year.

The holding company for Century Bank increased net interest income 11 percent during the third quarter, which rose to $18.6 million compared with $16.7 million last year. Other operating income totaled $3.8 million, compared with $3.7 million last year.

Total assets for the nine months ended Sept. 30 increased 6.4 percent to $3.9 billion, compared with $3.6 billion at year-end 2014.

Century Bancorp’s allowance for loan losses totaled $22.3 million, or 1.36 percent of outstanding loans, as of Sept. 30, compared with $22.5 million or 1.66 percent of outstanding loans a year ago. Nonperforming assets declined to $1.8 million at the end of the third quarter this year, compared with $6 million a year ago.

The company’s leverage ratio stood at 6.71 percent at the close of the third quarter, compared with 6.91 percent at year-end 2014, due to an increase in quarterly average assets and offset somewhat by an increase in stockholders’ equity, the company said. Book value as of Sept. 30 was $37.92 per share compared with $34.57 at Dec. 31, 2014.

The company’s board of directors voted a regular quarterly dividend of 12 cents per share on its Class A common stock, and 6 cents per share on its Class B common stock. Those dividends will be paid Nov. 16 to stockholders of record on Nov. 2.