SEC announcements that need to be understood when learning about U.S. stocks

There are generally 18 commonly used SEC announcements for U.S. stocks. Below is an introduction to the most frequently encountered ones: 1. S-1 / S-1/A The registration statement for initial public offerings (IPOs) by U.S.-based companies, containing all materials required for an IPO—including financial information, potential future dividend policies, competitors, market position, profitability, and more. S-1/A is a supplementary filing (‘A’ stands for Amendment), updating or correcting information omitted from the original S-1. 2. Form 6-K The document most frequently encountered by investors in Chinese概念股 (Chinese ADRs). It is used by Chinese ADR issuers to transmit quarterly and annual financial reports. 3. Form 10-K The annual report—a comprehensive overview of the company and its performance over the prior fiscal year (“official annual report”). Key contents include business summary, management’s discussion and analysis (MD&A), audited financial statements, details of outstanding debt, number of outstanding common shares, and warrant data. 4. Form 10-Q The quarterly report (‘Q’ stands for Quarter). Includes updated numbers of common shares outstanding, warrants outstanding, and financial information. Both 10-K and 10-Q are essential filings for anyone investing in U.S. stocks. 5. Form 8-K A current report—i.e., a mandatory disclosure filed upon occurrence of material corporate events. Examples include earnings announcements, tender offers, completed acquisitions, and capital markets transactions. Under U.S. securities law, companies must file an 8-K immediately upon such events to disclose relevant information. U.S.-based companies may also use Form 8-K to release earnings reports. Such 8-K earnings releases typically precede the corresponding 10-Q and resemble China’s A-share “preliminary earnings announcements.” However, financial data disclosed via 8-K are unaudited. 6. Proxy Statement A document provided by a public company to its shareholders ahead of the annual general meeting, outlining major matters on which shareholder votes are sought. 7. Schedule 13G / 13G/A Statements of beneficial ownership. Filed by any person or entity holding more than 5% of a company’s equity securities. When an investor or institution acquires, increases, or decreases its stake above/below the 5% threshold, it must publicly disclose this information with the SEC. Schedule 13G is generally filed when an investor first crosses the 5% ownership threshold; disclosures include shareholding percentage, number of shares, market value, and voting rights. Schedule 13G/A is a supplemental amendment filed after the initial 13G, to report subsequent changes (increases or decreases) in ownership. 8. Form 13F A quarterly filing required of institutional investment managers with at least $100 million in qualifying assets under management. It discloses their equity holdings, enhancing transparency and protecting retail investors’ interests. Institutions may, within legal limits, request confidential treatment for certain positions to prevent front-running or copycat trading. 9. Form 424B3 A prospectus supplement required when a company issues securities or security-related products. It provides detailed information about the offering to help investors assess its merits and make informed investment decisions.

At what time are earnings reports released? Use the SEC Form 8-K receipt time to verify pre-market/post-market labels

In my backtesting events, roughly half have unknown timing (empty or labeled as 'intraday'). The backtesting engine defaults to treating all such events as pre-market, entering positions at market open on the announcement date. This default appears harmless—but if a substantial portion of those 'unknown' events were actually released post-market, the backtested returns would be systematically inflated. (Real-time trading is unaffected: live signals only trigger *after* EPS is officially released, making pre-release entry impossible. The problem lies solely in backtesting evidence—and backtesting evidence is precisely what determines whether a strategy proceeds to live trading.) Method: Assign timing using the Form 8-K receipt timestamp U.S. public companies releasing earnings must file an 8-K, with earnings specifically reported under Item 2.02. EDGAR records the exact second each filing is received. This timestamp serves as an upper bound on the actual release time: press releases may precede the 8-K, but never follow it. Each event undergoes four steps: 1. Identify the filing: Within a window spanning from the trading day before the announcement date to the trading day after the entry date, select the earliest original 8-K (excluding amended 8-K/A filings) bearing Item 2.02 and closest in time to the event date. Do *not* use filingDate, because filings received after 17:30 ET are assigned a filingDate of the next business day. 2. Assign timing: Pre-market = before 9:30 ET; Intraday = 9:30–16:00 ET; Post-market = 16:00 ET onward. For half-day trading sessions (e.g., the day after Thanksgiving or Christmas Eve), the close is at 13:00 ET. Receipt timestamps falling on weekends or market holidays are assigned to the post-market session of the preceding trading day. 3. Compare with backtest entry time: If the 8-K was received before market open on the entry date, label the event 'pre-entry'—this conclusion remains valid even if the filing was delayed. If received at or after market close on the entry date, label it 'post-entry'; unless the press release predates the 8-K by a full trading session, such labeling indicates look-ahead bias. 4. No Item 2.02 found? First search other 8-Ks, then 10-Qs or 10-Ks, within the same window. If timing still cannot be determined, examine price reaction (intraday move and overnight gap on the announcement date). A strict precision threshold applies: only assign 'pre-market' if Wilson’s lower confidence bound for precision reaches 0.95; otherwise, leave it as 'undetermined'. Round 1: Stratified sampling by year and daily dollar volume yielded 200 'timing-unknown' events. Of these, 95 matched an Item 2.02 filing; additionally, 40 'pre-market'-labeled and 40 'post-market'-labeled events were sampled as controls. Round 2: All 3,203 remaining 'timing-unknown' events were timed (7,203 API requests, zero failures); all 3,585 previously timed events were re-verified. Result 1: ~60% of 'timing-unknown' events were filed *after* market close Among the 95 'timing-unknown' events matched to Item 2.02 in Round 1, 56 (58.9%; 95% CI: 48.9%–68.3%) were filed *after* market close on the backtest entry date; 8 were filed intraday; only 31 (32.6%) were confirmed filed before market open.

Sensient Technologies Files Form 8K After 14.77% Stock Drop

4 days ago

Sensient Technologies Corporation submitted a Form 8K to the SEC on October 30, triggered by a 14.77% decline in stock price. The specific details behind the regulatory filing were not disclosed in the report.

Investing.com Canada

2026-10-01

Sensient Technology Corporation Files 8-K Reports with SEC

2026-10-30

Sensient Technologies Files Form 8K After 14.77% Stock Drop

Sensient Technologies Files Form 8K After 14.77% Stock Drop

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