We analyze a market-wide panel dataset on retail option trading from India, which has an 80% share in option contracts traded worldwide. Retail participation is concentrated in and dominates index options trading. Traders exhibit short-term speculative behavior with significant day trading, short-duration directional bets, especially as options converge to 0DTE, and make significant losses. Three natural experiments show that financial constraints and lottery-like preferences shape investor behavior. An exogenous increase in the supply of short-maturity options induces trading. Lot-size increases and delivery margins trying to curb speculation are offset by speculative shifts to small ticket-size, riskier options. While stock market participation increases welfare in canonical household finance models, it can also entrench speculative behavior that is difficult to undo.

Investing in capital markets (stocks, bonds, ETFs, and mutual funds, etc.) helps preserve and grow wealth. Yet participation remains low, particularly among older, less affluent, and less educated individuals. Barriers like costs, investment thresholds, volatility, and limited financial literacy discourage engagement. While digitalization has eased these frictions and allowed for free access to financial education, participation remains low, at 30% in the U.K., 15% in Japan, and under 10% in China and India

We hypothesize that behavioral inertia, passive avoidance of unfamiliar opportunities, contributes to this gap. To test whether digital nudges can mitigate it, we analyze a quasi-natural experiment on a major Chinese platform. Among 560,000 users with no investment records, we randomly selected 64,770 who received prompts promoting low thresholds and diversified products, and free education; a control group, matched via Coarsened Exact Matching, received none.

The initial response rate was 1.5%, rising to 23.6% after six prompts. Of first-time responders, 32% invested an average of CNY 1,989 (~US$277). In the following months, these users, including older, less educated, and lower-income ones, built diversified portfolios and consistently outperformed the control group in risk-adjusted returns. The results show that digital nudges can help overcome inertia and broaden financial inclusion.