Total Cash and Cash Equivalents. Total cash and cash equivalents decreased $35.5 million, or 35.1%, to $65.5 million at December 31, 2017 from $101.0 million at September 30, 2017, as excess funds were redeployed principally to fund the purchase of investment securities.
Investment Securities. Total investment securities increased $260.1 million, or 37.7%, to $950.2 million at December 31, 2017 from $690.1 million at September 30, 2017. Consistent with our anticipated use of proceeds and to take advantage of then-existing investment opportunities in the securities market, we increased our position in investment securities utilizing short-term borrowings originated during the quarter ended December 31, 2017, with the intent to repay the borrowings with proceeds from the offering. At December 31, 2017, our total investment securities portfolio consisted of 74.8% of available-for-sale securities and 25.2% of securities held-to-maturity as compared to 80.7% and 19.3%, respectively, at September 30, 2017. At December 31, 2017, our investment portfolio comprised 16.5% of total assets.
Loans Receivable. Loans receivable, net, increased $92.8 million, or 2.2%, to $4.4 billion at December 31, 2017 from $4.3 billion at September 30, 2017. The increase was primarily the result of purchasing $49.8 million of commercial real estate and multifamily loans from a local community bank combined with an increase in residential loans of $38.2 million. The purchased loans were re-underwritten by Columbia Bank using its own underwriting standards.
Non-Performing Assets. Non-performing assets increased $696 thousand to $7.5 million, or 0.13% of total assets at December 31, 2017 from $6.8 million, or 0.13% of total assets at September 30, 2017.
Deposits. Deposits increased $139.9 million, or 3.4%, to $4.3 billion at December 31, 2017 from $4.1 billion at September 30, 2017. The increase was primarily the result of growth in interest-bearing and non-interest-bearing transaction accounts as well as certificates of deposit.
Borrowings. Borrowings increased $196.0 million, or 26.7%, to $929.1 million at December 31, 2017 from $733.0 million at September 30, 2017, primarily due to increases in short-term Federal Home Loan Bank of New York advances used to purchase investment securities as part of our leverage strategy noted above.
Stockholder’s Equity. Total stockholder’s equity decreased $3.8 million, or 0.8%, to $472.1 million at December 31, 2017 from $475.9 million at September 30, 2017. The decrease was the result of a $7.5 million increase in accumulated other comprehensive loss primarily attributable to a decline in the discount rate used to present value our pension benefit obligations, which was partially offset by net income of $3.7 million for the three months ended December 31, 2017.
On January 18, 2018, FASB released an Exposure Draft for a Proposed Standards Update, which sets forth a proposal to reclassify certain tax effects related to the revaluing of deferred tax assets triggered by the Tax Cuts and Jobs Act from retained income to other comprehensive income (loss). The reclassification under the Exposure Draft would not affect net income or total stockholder’s equity. The Company will continue to monitor the FASB’s consideration of the Exposure Draft, and evaluate the impact that any final Standards Update may have on the Company’s financial statements.
Comparison of Results of Operations for the Three Months Ended December 31, 2017 and 2016
General. Net income decreased $6.3 million, or 63.2%, to $3.7 million for the three months ended December 31, 2017 compared to $10.0 million for the three months ended December 31, 2016. The decrease was primarily attributable to a $4.1 million increase in income tax expense due to the revaluation of our net deferred tax assets as well as a $3.4 million increase in the provision for loan losses. These items were partially offset by a $3.5 million increase in net interest income.
Net Interest Income. Net interest income increased $3.5 million, or 10.5%, to $36.9 million for the three months ended December 31, 2017 compared to $33.4 million for the three months ended December 31, 2016. The increase was largely a result of an increase in interest income on loans of $3.7 million due to portfolio growth.
Interest and Dividend Income. Interest and dividend income increased $5.0 million, or 11.4%, to $49.2 million for the three months ended December 31, 2017 compared to $44.1 million for the three months ended December 31, 2016. The increase was primarily the result of increased average loan and