TRUCKEE, Calif. andamp;#8212; Investors in need of income in todayandamp;#8217;s volatile markets face some unique challenges. This is not your grandfatherandamp;#8217;s market. Interest rates are at all time lows while market volatility has recently been hitting all time highs.In a normal interest rate environment, investors can ladder high quality bonds and expect to receive decent cash flow. Many planners and investors use the 4 percent rule for withdrawals from retirement accounts.The 4 percent rule is also known as the andamp;#8220;Trinity Study.andamp;#8221; It was originally published in 1998 by three professors at Trinity College in Texas and applies to the ideal withdrawal rate of a retirement fund. The rule suggests that you withdraw 4 percent or your portfolio in the first year of retirement, then each year increase that by an inflation adjuster, the cash flow keeps up with inflation.Using that methodology retirees have a very high probability of seeing their funds last at least 30 years. In the original study, a 50-50 stock and bond portfolio had a 95 percent success rate.If treasury bonds were paying 7 percent or so, it would be a simple matter to design a portfolio that would meet or exceed the 4 percent rule. Today that is not so easy. Investors face record low interest rates, choppy markets and inflation.While growth investors can sit in cash during volatile markets and wait out periods of instability and falling equity prices, income investors often cannot. If income investors sit in cash at essentially 0 percent and withdraw at 4 percent to 5 percent, they are guaranteed that they will deplete their principle. Growth investors can sit on the sidelines in cash and wait for opportunities to invest.Income investors have a need for a steady, reliable stream of cash flow that is not so easy to find in todayandamp;#8217;s market without taking on an undesirable level of risk.Kenneth Roberts, a Truckee-based Registered Investment Advisor, has been in the securities business since 1992, has worked as a branch manager for a major Wall Street firm and is currently a portfolio manager for Fusion Asset Management. Information on his money management service can be found at http://www.fusiontargetretirement.com or by calling 775-675-8065. Past performance does not guarantee future results. Consult your financial adviser before purchasing any security.