Buy Stocks, ETFs, and Options From Your Phone: The Best Trading Apps of September 2026

The article ranks Fidelity, SoFi Invest and Morgan Stanley's ETRADE among leading mobile trading apps for September 2026, emphasizing $0 stock and ETF commissions, fractional-share access and mobile investing tools. Fidelity is positioned as the best all-around broker, SoFi for integrated banking and investing, and ETRADE for active traders using advanced charting and options analytics. The article notes Morgan Stanley manages $10.0 trillion in client assets across more than 20 million relationships.

Analysis

This is not a fundamental catalyst for either public ticker; the favorable platform framing is promotional and provides no evidence of account-growth, funded-account, trading-volume, or net-revenue-retention acceleration. For SOFI, Invest is principally a customer-acquisition and engagement feature rather than a near-term earnings driver: the economic value comes only if brokerage users deepen into deposits, direct deposit, lending, or advisory products. The relevant read-through is therefore cross-sell conversion and deposit retention, not retail trading activity alone.

MS has the opposite exposure profile. E*TRADE’s tools can support asset retention and options-order flow, but its impact is diluted within a much larger wealth-management franchise; a retail-app ranking cannot alter the earnings case without evidence of net new assets or improved fee yield. Competitive pressure from Fidelity, Robinhood (HOOD), Charles Schwab (SCHW), and Interactive Brokers (IBKR) keeps commissions structurally commoditized, so mobile-feature parity is more likely to raise technology and promotional expense than pricing power.

Over the next 1-3 months, monitor SOFI disclosures for Invest funded accounts, Invest balances, brokerage-to-bank product attachment, and customer-acquisition cost; a sustained increase in funded accounts without a corresponding rise in financial-services contribution margin would be negative. Over 6-18 months, the key structural question is whether integrated finance produces lower churn and cheaper deposit gathering than standalone brokers. Consensus may overvalue the engagement narrative: zero-commission brokerage can create transaction activity but not necessarily profitable customer lifetime value, particularly if cash balances migrate to higher-yield alternatives or promotions intensify.

Key Decisions for Investors

• No standalone event trade: treat this as a marketing-data point, not a catalyst, and avoid adding risk in SOFI or MS solely on the article.
• Maintain SOFI as a watch-long only if the next two quarterly reports show rising Invest balances and cross-sell alongside expanding Financial Services contribution margin; absent those metrics, brokerage growth may be revenue-light and promotion-heavy.
• For a relative-value expression, prefer long MS / short SOFI over a 6-12 month horizon if retail trading competition intensifies: MS has diversified wealth-management earnings, while SOFI has greater sensitivity to customer-acquisition efficiency and deposit monetization. Reassess if SOFI demonstrates sustained deposit growth and material margin expansion.
• Monitor HOOD, SCHW, and IBKR earnings for pricing, interest-on-cash, and trading-volume commentary. A broad increase in paid acquisition or lower net interest revenue from client cash would falsify any assumption that app engagement converts cleanly into brokerage profitability.