The new shares bring the QIA's ownership in Credit Suisse to 6.87%, amounting to 272.25 million shares, from 5.57% as reported in its last SEC filing in November.
Credit Suisse declined to comment when contacted by Reuters on Monday and the QIA did not immediately respond to a request for comment.
Credit Suisse's shares rose 2.2% on Monday to close at 3.15 Swiss francs.
SNB, along with the QIA and Olayan Group, account for about 20% of Credit Suisse shares.
Credit Suisse outlined plans in October to raise 4 billion Swiss francs from investors, cut thousands of jobs and shift its focus from investment banking towards its rich clients.