18. Commitments and Contingencies (a) Concentration of Credit Risk Fixed maturities The Companys investment portfolio is managed following prudent standards of diversification and a prudent investment philosophy. The Company is not exposed to any significant credit concentration risk on its investments, except for debt securities issued by the U.S. government and other highly rated non-U.S. sovereign governments securities. At December 31, 2015 and 2014 , other than the U.S. government, the Companys fixed maturity investment portfolio did not contain exposure to any non-U.S. sovereign government or any other issuer that accounted for more than 10% of the Companys shareholders equity attributable to PartnerRe. The Company keeps cash and cash equivalents in several banks and monitors significant concentrations of credit risk in any one bank. At December 31, 2015 , the Company held cash and cash equivalent of $1.2 billion with a high credit quality international bank which was primarily invested in United States government and government sponsored enterprises' money market funds. This concentration at December 31, 2015 was partially due to the timing of investment sale and purchase activity and certain specific cash requirements related to the closing of the Merger. Derivatives The Companys investment strategy allows for the use of derivative instruments, subject to strict limitations. Derivative instruments may be used to replicate investment positions and for the purpose of managing overall currency risk, market exposures and portfolio duration, for hedging certain investments, or for enhancing investment performance that would be allowed under the Companys investment policy if implemented in other ways. The Company is exposed to credit risk in the event of non-performance by the counterparties to the Companys derivative contracts. However, the Company diversifies the counterparties to its derivative contracts to reduce credit risk, and because the counterparties to these contracts are high credit quality