NEW YORK (TheStreet) -- The unusual trading action in Procter & Gamble(PG) stock believed to be at the center of the market's most volatile moments on Thursday is thought to have originated from Terra Nova Financial(TNFG), a Chicago-based provider of prime brokerage and clearing services, a person familiar with the situation has told TheStreet. TheStreet has been in contact with Terra Nova since this story was initially published and is awaiting an official statement from the company. The exact circumstances of the trading action are still unclear. Terra Nova has broker-dealer status with both the Securities and Exchange Commission and the Financial Industry Regulatory Authority, or FINRA. One of the services it offers is sponsored direct market access, which it says allows clients to "establish a direct connection between their proprietary platforms and the Nasdaq or NYSE Arca execution systems," so the trade -- characterized as a large sell order in P&G -- could have come from one of the firm's clients with this type of access. There is no indication of wrongdoing on Terra Nova's part at this time. Terra Nova's customers appear to be mostly hedge funds, but it also provides clearing services for other broker-dealers and registered investment advisers. Calls and e-mail inquiries to officials and press contacts at the SEC, FINRA, NYSE Euronext and Nasdaq OMX Group had yet to be returned late Sunday afternoon. The SEC is already moving toward clamping down on sponsored direct market access, which is often referred to as "naked" or "unfiltered" access, having proposed a new rule to effectively prohibit it back in January. "Unfiltered access is similar to giving your car keys to a friend who doesn't have a license and letting him drive unaccompanied," said SEC Chairman Mary Schapiro at the time. "Today's proposal would require that if a broker-dealer is going to loan his keys, he must not only remain in the car, but he must also see to it that the person driving observes the rules before the car is ever put into drive." The SEC says Rule 15c3-5 would put in place risk management controls and supervisory procedures that would, among other things, "help prevent erroneous orders," and it warned in January of the potential for orders "not being appropriately managed" under the sponsored DMA arrangements that essentially allow the broker-dealer to lease out their credentials for direct electronic access to an exchange or alternative trading systems, such as ECNs, to non-broker-dealer customers. ... http://www.thestreet.com/story/10750843/1/chicago-firm-linked-to-pg-trade-source.html?kval=dontmiss