The group reported earnings of 2.63 rupees for the quarter. For the six months to June it reported earnings of 6.20 rupees per share on total profits of 4.8 billion rupees, which were down 13 percent.
The stock closed at 120 rupees Wednesday.
Interest income for the June quarter rose 13.4 percent to 15.6 billion rupees from a year earlier, and interest expenses rose at a faster 29 percent to 9.3 billion rupees, but the bank grew net interest income 10.7 percent to 6.3 billion rupees.
Fee and commission income rose 18 percent to 1.0 billion rupees.
But the bank made 833 million rupees in trading losses, down from profits of 594 million rupees mostly on account of swap costs of foreign exchange funding as the rupee weakened during the quarter.
Loans and advances had grown 4.4 percent to 390 billion rupees in the six months to June.
"Signs of improving credit growth were witnessed during the latter part of the second quarter and this is expected to continue," the bank said in a statement.
Commercial Bank provided 1.2 billion rupees for bad loans up, 7.9 percent, with 388 million rupees in general provisions, up from a 6.2 million reversal a year earlier.
The gross non-performing loan ratio rose to 4.04 percent by end June from 3.37 percent in December.
Sri Lanka is recovering from a balance of payments crisis, and higher defaults, slow credit and stronger deposits growth are usual outcomes.
Group gross assets rose 9 percent to 558 billion rupees and net assets rose 4.9 percent to 55.6 billion rupees.
The bank's core capital adequacy rose to 13.85 percent to by June from 12.63 percent in December and total capital rose to 17.7 percent and 13.8 percent helped by a 75 million US dollar 10 year junior debt from International Finance Corporation.