performance of our services and products. We do not expect any material losses related to such representations and warranties. Quantitative and Qualitative Disclosures about Market Risk Our overall investment portfolio is comprised of corporate investments (cash and cash equivalents, and long-term marketable securities) and client funds assets (funds that have been collected from clients but have not yet remitted to the applicable tax authorities or client employees). Our corporate investments are invested in cash and cash equivalents and highly liquid, investment-grade marketable securities. These assets are available for our regular quarterly dividends, share repurchases, capital expenditures and/or acquisitions, as well as other corporate operating purposes. All of our long-term fixed-income securities are classified as available-for-sale securities. Our client funds assets are invested with safety of principal, liquidity, and diversification as the primary objectives. Consistent with those objectives, we also seek to maximize interest income and to minimize the volatility of interest income. Client funds assets are invested in highly liquid, investment-grade marketable securities, with a maximum maturity of 10 years at the time of purchase, and money market securities and other cash equivalents. We utilize a strategy by which we extend the maturities of our investment portfolio for funds held for clients and employ short-term financing arrangements to satisfy our short-term funding requirements related to client funds obligations. Our client funds investment strategy is structured to allow us to average our way through an interest rate cycle by laddering the maturities of our investments out to five years (in the case of the extended portfolio) and out to ten years (in the case of the long portfolio). As part of our client funds investment strategy, we use the daily collection of funds from our clients to satisfy other unrelated client funds obligations, rather than liquidating previously-collected client funds that have already been invested in available-for-sale securities. In circumstances where we experience a reduction in employment levels due to a slowdown in the economy, we may make tactical decisions to sell certain securities in order to reduce the size of the funds held for clients to correspond to client fund obligations. We minimize the risk of not having funds collected from a client available at the time such client’s obligation becomes due by impounding, in virtually all instances, the client’s funds in advance of the timing of payment of such client’s obligation. As a result of this practice, we have consistently maintained the required level of client funds assets to satisfy all of our obligations. There are inherent risks and uncertainties involving our investment strategy relating to our client funds assets. Such risks include liquidity risk, including the risk associated with our ability to liquidate, if necessary, our available-for-sale securities in a timely manner in order to satisfy our client funds obligations. However, our investments are made with the safety of principal, liquidity, and diversification as the primary goals to minimize the risk of not having sufficient funds to satisfy all of our client funds obligations. We also believe we have significantly reduced the risk of not having sufficient funds to satisfy our client funds obligations by consistently maintaining access to other sources of liquidity, including our corporate cash balances, available borrowings under our $ 9.7 billion  commercial paper program (rated A-1+ by Standard and Poor’s and P-1 by Moody’s, the highest possible short-term credit ratings), and our ability to engage in reverse repurchase agreement transactions and available borrowings under our $9.7 billion committed credit facilities. The reduced availability of financing during periods of economic turmoil, including the COVID-19 pandemic, even to borrowers with the highest credit ratings, may limit our ability to access short-term debt markets to meet the liquidity needs of our business. In addition to liquidity risk, our investments are subject to interest rate risk and credit risk, as discussed below. We have established credit quality, maturity, and exposure limits for our investments. The minimum allowed credit rating at time of purchase for corporate, Canadian government agency and Canadian provincial bonds is BBB, for asset-backed securities is AAA, and for municipal bonds is A. The maximum maturity at time of purchase for BBB-rated securities is 5 years, for single A rated securities is 7 years, and for AA-rated and AAA-rated securities is 10 years. Time deposits and commercial paper must be rated A-1 and/or P-1. Money market funds must be rated AAA/Aaa-mf.