CommerceBancorp, the holding company for CommerceBank in Newport Beach, reported net income of $1.6 million for 1987, a 28% increase over the $1.25 million reported for the previous year. Net income for the fourth quarter rose 44.65% to $460,000, from $318,000 for that period in 1986. CommerceBancorp was formed in 1987, and the bank is its chief asset. The 1986 earnings are those of the bank. Total assets declined 7.5% to $217.4 million at the end of December, from $235 million for December, 1986, mainly because deposits at the end of 1986 were abnormally high. Total deposits fell 7.5% to $203.2 million at the end of December, from $219.6 million a year earlier; net loans grew 17.6% to $134.4 million at the end of the year, from $114.3 million a year earlier.