Last Friday's Weekly Financial Statistics release marks the end of the Bank of Canada's policy of providing liquidity to financial markets by means of securities purchased under resale agreements (SPRA). In the first three months following the introduction of these measures in September 2008, the Bank's balance sheet increased by 56%, and almost half of its assets - some $38b - took the form of SPRA (see also this post).
As the liquidity crisis receded, the Bank announced that it would be unwinding its SPRA holdings, and this operation was completed sometime last week. Here is a graph of the evolution of the asset side of its balance sheet.
On the liabilities side, the expansion of the balance sheet was achieved by increasing the federal government's deposits at the Bank of Canada:
Having the federal government hold those increased liabilities simplified matters somewhat; presumably it would be more willing to coordinate its activities with those of the Bank than private banks would have been.