 <p>If they are daily returns and you want a cumulative return, surely you must want a daily compounded number?</p> <pre><code>df['perc_ret'] = (1 + df.Daily_rets).cumprod() - 1 &gt;&gt;&gt; df Poloniex_DOGE_BTC Poloniex_XMR_BTC Daily_rets perc_ret 172 0.006085 -0.000839 0.003309 0.003309 173 0.006229 0.002111 0.005135 0.008461 174 0.000000 -0.001651 0.004203 0.012700 175 0.000000 0.007743 0.005313 0.018080 176 0.000000 -0.001013 -0.003466 0.014551 177 0.000000 -0.000550 0.000772 0.015335 178 0.000000 -0.009864 0.001764 0.017126 </code></pre>