x   ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF

For the fiscal year ended December 31, 2015

o  TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF

For the transition period from to

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Act. Yes x No o

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes o No x

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes x  No o

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files). Yes x  No o

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§229.405 of this chapter) is not contained herein, and will not be contained, to the best of registrant’s knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K. o

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or a smaller reporting company, as defined in Rule 12b-2 of the Act. Large accelerated filer x, Accelerated filer o, Non-accelerated filer o, Smaller reporting company o

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes o  No x

The aggregate market value of Common Shares held by nonaffiliates of the registrant at June 30, 2015 was $4,564.8 million based on the closing sale price of the Common Shares on the New York Stock Exchange on that date.

The number of Common Shares, par value US $1.00 per share, outstanding at February 18, 2016 was 43,144,615.

Portions of the registrant’s definitive proxy statement for the 2016 Annual General Meeting of Shareholders are incorporated by reference into Part III of this report.

RenaissanceRe was established in 1993 and is a leading global provider of reinsurance and insurance coverages and related services. Our aspiration is to be the world’s best underwriter by matching well-structured risks with efficient sources of capital. Through our operating subsidiaries, we seek to produce superior returns for our shareholders by being a trusted, long-term partner to our customers for assessing and managing risk, and by delivering responsive solutions. We accomplish this by leveraging our core capabilities of risk assessment and information management, by investing in our capabilities to serve our customers across the cycles that have historically characterized our markets and by keeping our promises. Overall, our strategy focuses on superior risk selection, superior customer relationships and superior capital management. We provide value to our customers and joint venture partners in the form of financial security, innovative products, and responsive service. We are known as a leader in paying valid reinsurance claims promptly. We principally measure our financial success through long-term growth in tangible book value per common share plus the change in accumulated dividends, which we believe is the most appropriate measure of our Company’s financial performance, and believe we have delivered superior performance in respect of this measure over time.

On March 2, 2015, RenaissanceRe acquired Platinum pursuant to a definitive merger agreement entered into on November 23, 2014. As a result of the acquisition of Platinum, Platinum and its operating subsidiaries became wholly owned subsidiaries of RenaissanceRe. In connection with an intercompany restructuring, effective July 1, 2015, Platinum was merged with RenaissanceRe, with RenaissanceRe continuing as the surviving company. Refer to “Part II, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations, Summary Results of Operations and Liquidity and Capital Resources, Impact of Platinum Acquisition on Liquidity and Capital Resources” and “Note 3. Acquisition of Platinum” in the notes to our consolidated financial statements for additional information with respect to the acquisition of Platinum.

Superior Customer Relationships.  We seek to be a trusted long-term partner to our customers for assessing and managing risk and delivering responsive solutions. We believe our modeling and technical expertise, our risk management products we provide our customers and our track record of keeping our promises have made us a provider of first choice in many lines of business to our customers worldwide.  We seek to offer stable, predictable, and consistent risk-based pricing and a prompt turnaround on claims.

Superior Risk Selection.  We seek to build a portfolio of risks that produces an attractive risk-adjusted return on utilized capital.  We develop a perspective of each risk using both our underwriters’ expertise and sophisticated risk selection techniques, including computer models and databases such as Renaissance Exposure Management System (“REMS©”).  We pursue a disciplined approach to underwriting and seek to select only those risks we believe will produce a portfolio with an attractive return, subject to prudent risk constraints.  We manage our portfolio of risks dynamically, both within sub-portfolios and across the Company.

Superior Capital Management.  We seek to write as much attractively priced business as is available to us and then manage our capital accordingly.  We generally seek to raise capital when we forecast increased demand in the market, at times by accessing capital through joint ventures or other structures, and seek to return capital to our shareholders or joint venture investors when the demand for our coverages appears to decline and when we believe a return of capital would be beneficial to our shareholders or joint venture investors.  In using joint ventures, we intend to leverage our access to business and our underwriting capabilities on an efficient capital base, develop fee income, generate profit commissions, diversify our portfolio and provide attractive risk-adjusted returns to our capital providers. We routinely evaluate and review potential joint venture opportunities and strategic investments.

For the year ended December 31, 2015, our Catastrophe Reinsurance, Specialty Reinsurance and Lloyd’s segments accounted for 43.2%, 38.1% and 18.7%, respectively, of our total consolidated gross premiums written. Contributions to our consolidated results from our Specialty Reinsurance and Lloyd’s segments have increased in recent years, and we expect them to continue to increase over time, on both an absolute and relative basis, although we cannot assure you that this trend will continue. Operating results relating to our segments are included in “Part II, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations.”

Our portfolio of business continues to be characterized by relatively large transactions with ceding companies with whom we do business, although no current relationship exceeds 10% of our gross premiums written. Accordingly, our gross premiums written are subject to significant fluctuations depending on our success in maintaining or expanding our relationships with these customers. We market our reinsurance products worldwide exclusively through brokers, whose market has become increasingly consolidated in recent years.  In 2015, three brokerage firms accounted for 81.5% of our Catastrophe Reinsurance and Specialty Reinsurance segments’ gross premiums written.  We believe that recent market dynamics, and trends in our industry in respect of recent and potential future consolidation, have increased our exposure to the risks of broker, client and counterparty concentration.

The following table shows our gross premiums written split between our Catastrophe Reinsurance, Specialty Reinsurance and Lloyd’s segments, respectively:

(1) Included in gross premiums written in the Other category is inter-segment gross premiums written of $(0.1) million for the year ended December 31, 2015 (2014 - $0.3 million, 2013 - $(1.0) million).

Our Other category primarily includes the results of: (1) our share of strategic investments in certain markets we believe offer attractive risk-adjusted returns or where we believe our investment adds value, and where, rather than assuming exclusive management responsibilities ourselves, we partner with other market participants; (2) our investment unit which manages and invests the funds generated by our consolidated operations; (3) corporate expenses, certain expenses related to the acquisition of Platinum, capital servicing costs and noncontrolling interests; (4) the results of our discontinued operations; and (5) the remnants of our Bermuda-based insurance operations.

DaVinci was established in 2001 and principally writes property catastrophe reinsurance and certain low frequency, high severity specialty reinsurance lines of business on a global basis. In general, we seek to construct for DaVinci a property catastrophe reinsurance portfolio with risk characteristics similar to those of Renaissance Reinsurance’s property catastrophe reinsurance portfolio and a portfolio of certain lines of specialty reinsurance such as terrorism and catastrophe exposed workers’ compensation. In accordance with DaVinci’s underwriting guidelines, it can only participate in business that is underwritten by Renaissance Reinsurance. We maintain majority voting control of DaVinci’s holding company, DaVinciRe, and accordingly, consolidate the results of DaVinciRe into our consolidated results of operations and financial position. We seek to manage DaVinci’s capital efficiently over time in light of the market opportunities and needs we perceive and believe we are able to serve. Our noncontrolling economic ownership in DaVinciRe was 26.3% at December 31, 2015 (2014 - 23.4%).

Medici is an exempted fund, incorporated under the laws of Bermuda. Medici’s objective is to invest substantially all of its assets in various insurance-based investment instruments that have returns primarily correlated to property catastrophe risk. Third-party investors subscribe for a portion of the participating, non-voting common shares of Medici. We maintain majority voting control of Medici’s parent, RenaissanceRe Fund Holdings Ltd. (“Fund Holdings”), therefore the results of Medici and Fund Holdings are consolidated in our financial statements. Our economic ownership in Medici was 46.1% at December 31, 2015 (2014 - 53.2%).

Effective November 13, 2014, we incorporated Upsilon Fund, an exempted Bermuda limited segregated accounts company. Upsilon Fund was formed to provide a fund structure through which third party investors can invest in reinsurance risk managed by us. As a segregated accounts company, Upsilon Fund is permitted to establish segregated accounts to invest in and hold identified pools of assets and liabilities. Each pool of assets and liabilities in each segregated account is ring-fenced from any claims from the creditors of Upsilon Fund’s general account and from the creditors of other segregated accounts within Upsilon Fund. Third party investors purchase redeemable, non-voting preference shares linked to specific segregated accounts of Upsilon Fund and own 100% of these shares. Upsilon Fund is managed by RenaissanceRe Fund Management Ltd. in return for an expense override and profit commission. We have not provided any financial or other support to Upsilon Fund we were not contractually required to provide. Currently, Upsilon Fund is invested in Upsilon RFO and Medici.

Our exposures are generally diversified across geographic zones, but are also a function of market conditions and opportunities. Our largest exposure has historically been to the U.S. and Caribbean market, which represented 59.4% of our gross premiums written for the year ended December 31, 2015. A significant amount of our U.S. and Caribbean premium provides coverage against windstorms (mainly U.S. Atlantic hurricanes), earthquakes and other natural and man-made catastrophes. The following table sets forth the percentage of our gross premiums written allocated to the territory of coverage exposure:

Reserve Risk is a subcomponent of assumed risk. We define reserve risk as the risks related to our reserve for net claims and claim expenses, including the amount, both absolute and relative, of our outstanding reserve for net claims and claim expenses, and the impact of economic, social, legal and regulatory matters. Our reserve for net claims and claim expenses is subject to significant uncertainty as a result of these factors, and others. Although reserve risk can increase in both the absolute, and relative to its overall consideration in our ERM framework, we employ robust resources, procedures and technology to identify, understand, quantify and manage these risks. Our reserve risk has increased in recent years, and specifically the acquisition of Platinum added claims and claim expense reserves of $1.4 billion at March 2, 2015, consisting of $117.4 million and $1.3 billion included in our Catastrophe Reinsurance and Specialty Reinsurance segments, respectively, which are subject to the reserving methodologies and sensitivities for each respective line of business described in “Part II. Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations, Summary of Critical Accounting Estimates, Claims and Claim Expense Reserves.” Our reserve for net claims and claim expenses will continue to be subject to significant uncertainty and has the potential to develop adversely in future periods.

Controls and Compliance Committee.  We believe that a key component of our current operational risk management platform is our Controls and Compliance Committee. The Controls and Compliance Committee is comprised of our CFO, CCO, CAO, CRO, Head of Internal Audit, staff compliance professionals and representatives from our business units. The purpose of the Controls and Compliance Committee is to establish, assess the effectiveness of, and enforce policies, procedures and practices relating to accounting, financial reporting, internal controls, regulatory, legal, compliance and related matters, and to ensure compliance with applicable laws and regulations, the Company’s Code of Ethics and Conduct (the “Code of Ethics”), and other relevant standards. In addition, the Controls and Compliance Committee is charged with reviewing certain transactions that potentially raise complex and/or significant tax, legal, accounting, regulatory, financial reporting, reputational or compliance issues.

Ongoing Development and Enhancement.  We seek to reflect and categorize risks we monitor in part through quantitative risk distributions, even where we believe that such quantitative analysis is not as robust or well developed as our tools and models for measuring and evaluating other risks, such as catastrophe and market risks. We also seek to improve the methods by which we measure risks. Effective risk management is a core attribute of our culture and we believe it is a continual process that requires ongoing improvement and development. We seek from time to time to identify effective new practices or additional developments both from within our industry and from other sectors. We believe that our ongoing efforts to embed ERM throughout our organization are important to our efforts to produce and maintain a competitive advantage to achieve our corporate goals.

In connection with the acquisition of Platinum on March 2, 2015, we acquired claims and claim expense reserves of $1.4 billion, consisting of $117.4 million and $1.3 billion included in our Catastrophe Reinsurance and Specialty Reinsurance segments, respectively, which are subject to the reserving methodologies for each respective line of business as described in “Part II, Item 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations, Summary of Critical Accounting Estimates, Claims and Claim Expense Reserves.”

The following table summarizes our claims and claim expense reserves by line of business, split between case reserves, additional case reserves and IBNR:

Our estimates of claims and claim expense reserves are not precise in that, among other matters, they are based on predictions of future developments and estimates of future trends and other variable factors. Some, but not all, of our reserves are further subject to the uncertainty inherent in actuarial methodologies and estimates. Because a reserve estimate is simply an insurer’s estimate at a point in time of its ultimate liability, and because there are numerous factors which affect reserves and claims payments that cannot be determined with certainty in advance, our ultimate payments will vary, perhaps materially, from our estimates of reserves. If we determine in a subsequent period that adjustments to our previously established reserves are appropriate, such adjustments are recorded in the period in which they are identified. During the year ended December 31, 2015, changes to prior year estimated claims reserves increased our net income by $162.4 million (2014 - $143.8 million, 2013 - $144.0 million), excluding the consideration of changes in reinstatement premium, profit commissions, redeemable noncontrolling interest - DaVinciRe, equity in net claims and claim expenses of Top Layer Re and income tax.

The following table presents an analysis of our paid, unpaid and incurred losses and loss expenses and a reconciliation of beginning and ending reserves for claims and claim expenses for the years indicated:

Our reserving methodology for each line of business uses a loss reserving process that calculates a point estimate for our ultimate settlement and administration costs for claims and claim expenses. We do not calculate a range of estimates. We use this point estimate, along with paid claims and case reserves, to record our best estimate of additional case reserves and IBNR in our consolidated financial statements. Under GAAP, we are not permitted to establish estimates for catastrophe claims and claim expense reserves until an event occurs that gives rise to a loss.

Reserving for our reinsurance claims involves other uncertainties, such as the dependence on information from ceding companies, which among other matters, includes the time lag inherent in reporting information from the primary insurer to us or to our ceding companies and differing reserving practices among ceding companies. The information received from ceding companies is typically in the form of bordereaux, broker notifications of loss and/or discussions with ceding companies or their brokers. This information may be received on a monthly, quarterly or transactional basis and normally includes paid claims and estimates of case reserves. We sometimes also receive an estimate or provision for IBNR. This information is often updated and adjusted from time to time during the loss settlement period as new data or facts in respect of initial claims, client accounts, industry or event trends may be reported or emerge in addition to changes in applicable statutory and case laws.

retrocessional contracts poses further challenges compared to directly assumed reinsurance. The contingent nature of business interruption and other exposures will also impact losses in a meaningful way, which we believe may give rise to significant complexity in respect of claims handling, claims adjustment and other coverage issues, over time. Given the magnitude of certain events, there can be meaningful uncertainty regarding total covered losses for the insurance industry and, accordingly, several of the key assumptions underlying our loss estimates. In addition, our actual net losses from these events may increase if our reinsurers or other obligors fail to meet their obligations.

Because of the inherent uncertainties discussed above, we have developed a reserving philosophy which attempts to incorporate prudent assumptions and estimates, and we have generally experienced favorable net development on prior accident years net claims and claim expenses in the last several years. However, there is no assurance that this favorable development on prior accident years net claims and claim expenses will occur in future periods.

The following table represents the development of our GAAP balance sheet reserves for December 31, 2005 through December 31, 2015. This table does not present accident or policy year development data. The top line of the table shows the gross reserves for claims and claim expenses at the balance sheet date for each of the indicated years. This represents the estimated amounts of claims and claim expenses arising in the current year and all prior years that are unpaid at the balance sheet date, including additional case reserves and IBNR reserves. Net reserves for claims and claim expenses of Platinum are included in the year of acquisition. The table also shows the re-estimated amount of the previously recorded reserves based on experience as of the end of each succeeding year. The estimate changes as more information becomes known about the frequency and severity of claims for individual years. The “cumulative redundancy on net reserves” represents the aggregate change to date from the indicated estimate of the gross reserve for claims and claim expenses, net of reinsurance recoverable on the second line of the table. The table also shows the cumulative net paid amounts as of successive years with respect to the net reserve liability. At the bottom of the table is a reconciliation of the gross reserve for claims and claim expenses to the net reserve for claims and claim expenses, the gross re-estimated liability to the net re-estimated liability for claims and claim expenses, and the cumulative redundancy on gross reserves.