These funds also have model portfolios you can choose, online tools to help you assess how much risk you want to take, and what fund choices will match up best with your desired level of risk. The age and-younger limit is called a Section limit. The limited applicability of the strategy was rarely explained. The ability to expand investment horizons is one of a SD k ‘s main features. The catch-up contributions can be made in addition to the Section limit, which is what makes the age 50 total contribution limit equal to the Section limit plus the maximum allowable catch-up contribution. The main benefit of a solo k is that, for the most part, they can legally be used to invest in almost anything, which can include real estate, tax liens, precious metals, foreign currency, or even money lending.