PCOrder (D) conducted an initial public offering on February 26, 1999, and a secondary public offering on December 7, 1999. D filed a registration statement with the SEC. Ps filed lawsuits against D under Section 11 of the Securities Act of 1933, which provides a right of action to 'any person acquiring' shares issued pursuant to an untrue registration statement. Ps alleged that the registration statements were false and misleading by indicating that D had a viable business plan, had an ability to generate and report accurate operating and financial information, and was not competing with Trilogy Software for revenue. The district court first found that none of the lead plaintiffs purchased their stock during the public offerings--that is, they were 'aftermarket' purchasers. It held that Section 11 is also available to aftermarket purchasers as long as the stock is 'traceable' back to the relevant public offering. The district court found that the approximately 2.5 million shares issued in the D IPO were registered in a stock certificate in the name of Cede & Co., the nominee of the Depository Trust Company. The court found that, on April 19, 1999, when Beebe (P) purchased 1000 of these 'street name' shares, the pool of street name stock still contained only the IPO stock. Therefore, because all of his stock was necessarily IPO stock, Beebe (P) was able to satisfy the traceability requirement and establish standing. When Dr. Burke purchased 3000 shares, the court found that non-IPO shares--specifically, insider shares--had entered the street name certificate and intermingled with the IPO shares, but that IPO shares still comprised 99.85% of the pool. Subsequent to the December 7, 1999, secondary public offering, Dr. Burke made additional purchases and Petrick also purchased a number of shares at a time when IPO and SPO shares constituted 91% of the market. Ps' expert acknowledged that there is no way to track individual shares within a pool once it becomes contaminated with outside shares. Even though offering stock was the overwhelming majority--the district court held that Dr. Burke and Petrick could not demonstrate that their shares were traceable to the public offering. Expert testimony indicated that given the number of shares owned by each Lead Plaintiff and the percentage of PO stock in the market, the probability that each Lead Plaintiff owned at least one share of PO stock was very nearly 100%. The court held that this did not satisfy the traceability requirement because the 'Lead Plaintiffs must demonstrate all stock for which they claim damages was actually issued pursuant to a defective statement. The district court granted D's motion to dismiss for lack of subject matter jurisdiction. Only Beebe (P) had standing to sue under Section 11. The court then dismissed Beebe's (P) claim as moot because D had offered Beebe (P) a settlement equal to his full recovery under the statute. The district court denied a motion to intervene by three individuals. Ps appealed.