Capital Management. We continue to focus on capital management and maintain our capital at an appropriate level. In 2017, we repurchased 648,941 ordinary shares for a total consideration of $30.0 million. In addition, in the second quarter of 2017, we increased our quarterly dividend on our ordinary shares from $0.22 to $0.24 per ordinary share. On February 8, 2017, our Board of Directors also authorized a new share repurchase program of $250.0 million. The share repurchase authorization, which is effective through February 8, 2019, permits us to effect repurchases from time to time through a combination of transactions.
In 2017, gross written premiums in our reinsurance segment increased by 9.6% compared to 2016 due primarily to growth in specialty reinsurance business lines. The 4.5% increase in gross written premiums in our insurance segment in 2017 was due to growth in financial and professional lines insurance. Overall gross written premiums in 2017 increased by 6.8%. In 2016 gross written premiums increased by 5.0% compared to 2015 due primarily to growth in specialty reinsurance and casualty reinsurance business lines.
Includes gross written premium of $269.7 million (2016 - $178.9 million, 2015 -$Nil) related to AgriLogic.
Expenses. We monitor the ratio of expenses to gross earned premium (the “gross expense ratio”) as a measure of the cost effectiveness of our amortization of deferred policy acquisition costs, general, administrative and corporate expenses. The tables below present the contribution of the amortization of deferred policy acquisition costs and general, administrative and corporate expenses to the gross expense ratios and the total net expense ratios for the twelve months ended December 31, 2017, 2016 and 2015. We also show the effect of reinsurance purchased which impacts the reported net expense ratio by expressing the expenses as a proportion of net earned premiums.
As at December 31, 2017, we held foreign exchange contracts that were designated as hedging under ASC 815 with a notional amount of $60.6 million (2016 - $108.6 million). The foreign exchange contracts are recorded as derivatives at fair value in the balance sheet with the effective portion recorded in other comprehensive income and the ineffective portion recorded as a change in fair value of derivatives in the statement of operations. The contracts are considered to be effective and therefore the movement in other comprehensive income representing the effective portion was a gain of $3.0 million for the twelve months ended December 31, 2017 (December 31, 2016 - gain of $0.7 million).
Net premiums earned. Net premiums earned decreased by $354.9 million, or 24.4%, in 2017 compared to 2016 due to the impact from the increase in ceded written premiums. Net premiums earned increased by $54.7 million, or 3.9%, in 2016 compared to 2015 due to written premium growth in 2016 and the impact from the increases in ceded written premiums in 2016 not flowing into earnings until 2017.
Losses and loss adjustment expenses. The loss ratio in 2017 was 79.8% compared to 63.1% in 2016. The increase in the loss ratio in 2017 was primarily due a $57.1 million increase in catastrophe losses, an $18.7 million decrease in prior year reserve releases, a $34.4 million increase in large losses, an increase in attritional losses in U.S. property, primary casualty and management liability classes and a decrease in net earned premiums. The loss ratio in 2016 increased from 62.4% in 2015 due primarily to a $23.4 million reduction in prior year reserve releases and a $10.7 million increase in catastrophe losses.
ratings actions and general macro-economic conditions. There was a $0.7 million OTTI charge for the twelve months ended December 31, 2017 (2016 -$Nil).
twelve months ended December 31, 2015, our cash flows from operations provided us with sufficient liquidity to meet our operating requirements. We paid net claims of $1,108.5 million in 2015, and used $501.9 million in investing and net purchases and sales of equipment during the period. We paid ordinary and preference share dividends of $88.7 million, and $83.7 million was used to repurchase ordinary shares. At December 31, 2015, we had a balance of cash and cash equivalents of $1,099.5 million.
Our calculation of reserves for losses and loss expenses in respect of casualty business includes assumptions about future payments for settlement of claims and claims-handling expenses, such as medical treatments and litigation costs. We write casualty