An overview and introduction to common SEC filings in U.S. equities

For those unfamiliar with U.S. equities, reading articles related to U.S. stocks can often be confusing—terms like “F-1,” “20-F,” and “424(b)(4)” may leave readers utterly bewildered. These are collectively known as “SEC Filings”: formal documents—including financial statements—submitted to the U.S. Securities and Exchange Commission (SEC) by public companies, corporate insiders, and broker-dealers. Each abbreviation denotes a distinct filing type, applicable to specific circumstances. Many articles use these abbreviations directly, largely because translating them into Chinese is cumbersome: accurate translations often require lengthy, convoluted phrasing that makes sentences unwieldy and hard to follow—whereas widely accepted English acronyms remain crisp and efficient. Industry insiders naturally understand these terms, but newcomers often find them perplexing. Accordingly, this article systematically categorizes commonly used SEC filings and explains each—in plain, accessible language.

Insider Trading Analysis — AI Semiconductor Supply Chain Tracking SEC Form 4 insider trading filings across 53 core AI semiconductor companies. Data sourced from the SEC’s EDGAR database, refreshed every 5 minutes—so you’re among the first to know what insiders are buying or selling. What can this tool do for you? Form 4 filings are mandatory public disclosures required by the SEC: corporate executives, directors, and shareholders holding ≥10% of a company’s stock must file within two business days after executing any transaction. By systematically tracking these filings, you gain insight into insiders’ genuine sentiment toward their own stock—are they putting real money on the line to buy, or aggressively offloading shares? Page Navigation Overview Instantly grasp capital flow across the entire supply chain. Key summary cards display metrics including number of transactions, total buy/sell amounts, net sell amount, and sell-pressure ratio. Below lies the most practical feature—the real-time Filing Feed: a collapsible, company-level summary of every insider trade over the past three days. By default, only aggregated company-level data (e.g., net sell amount) is shown; click to expand and view full transaction details—who sold, their position, execution price, and transaction value. Group Overview Six horizontal group comparisons: Core Semiconductors (30 companies, e.g., NVDA, AMD, ARM), Optical Interconnects (12 companies, e.g., ANET, ALAB), Memory (e.g., MU), Data Center Infrastructure (13 companies, e.g., PLTR, CLS), M7 Tech Giants, and the Full AI Semiconductor Universe. Each group card displays buys/sells/net amount/sell-pressure ratio/number of insiders/median reduction magnitude; click through to see complete group-level details. Comparison All groups appear side-by-side in a single table—enabling direct comparison of sell pressure, median sell amount, P90 large-scale trades, and shareholding reduction magnitude. At the bottom, a sell-pressure heatmap and comparative reduction-distribution chart help you quickly identify which sector’s insiders are most actively divesting.