Until very recently, direct indexing was simply not an option for the vast majority of investors.  This is because the strategy is quite tedious to execute and could become cost prohibitive in the previous era when commission-free trading and fractional shares were not available.

This is because the strategy requires creating an actual index within an investors’ portfolio. It’s now feasible and quite easy to do due to technological advances. Additionally, the real alpha in the strategy is created through routine tax loss harvesting. 

This is an automated process where the portfolio is regularly scanned to sell off losing positions. Then, these losses can be used to offset capital gains elsewhere in the portfolio. Proceeds from the sold positions are then reinvested into stocks with similar factor scores to the ones that are sold in order to ensure integrity with the underlying index even if the holdings temporarily deviate. 

Clearly, this strategy wouldn’t be tenable without cheap and/or free trading and fractional shares for smaller sums. In the previous era, the high volume of trades would offset any additional returns. Without fractional trading, smaller sums also would not be able to track the underlying index and not be able to invest in higher-priced stocks that comprise large portions of indices. 

Finsum: Direct indexing’s proliferation is only possible due to 2 specific fintech breakthroughs - commission-free trading and fractional shares.