The phrase "cashing out" refers to the act of converting assets or investments into cash. An antonym for the term would be "investing in," which refers to the act of putting money into a particular venture or asset. Another antonym for "cashing out" would be "holding onto," which refers to the act of keeping an asset or investment rather than selling it. "Accumulating" is another antonym, which means to steadily build up an asset or investment over time rather than liquidating it all at once. Finally, "reinvesting" can also be an antonym for "cashing out," which refers to the act of reinvesting profits or dividends rather than drawing them out in cash.