Including the current S&P 500 daily winning streak there have been 233 six-day (or longer) Winning streaks by S&P 500 since 1950. The current 8-day streak has added 6.4% to the S&P 500 since it began on October 30. This is better than the average performance of the past 34 times that S&P 500 has been up eight days in-a-row, but well below the 11.9% S&P climbed in an eight-trading-day streak from March 12 to March 21, 2003.
History cannot tell us when this current streak will end. However, it does indicate increasingly longer streaks are infrequent. Although S&P 500 has gone as long as 14 days without a decline (March 26 to April 15, 1971), it has done so just once in nearly 74 years. When the streak does end, all is not lost. As you can see in the following chart of the 30 trading days before and 60 trading days after the past 7-, 8-, and 9-day daily winning streaks ended, S&P 500 continued to move higher on average over the next 60 trading days.