Dan David, cofounder of Skippack-based GeoInvesting L.L.C., has been tracking China-based firms listed on the New York and Nasdaq stock markets - and exposing what he says are phony sales, sham transactions, and investor rip-offs. He has been doing this since the China stock boom of the late 2000s, for clients that include short-sellers and other investors.

David cites examples like Sino Forest, which exaggerated its timber holdings, and China MediaExpress Holdings, which exaggerated sales, before they were delisted by Western exchanges. He also identified Puda Coal and poultry-raiser Yuhe International, which have traded at penny-stock prices since GeoInvesting published reports questioning their financial statements.

These companies cost shareholders millions, while investors who bet against them made money.

GeoInvesting's latest report targeted New York Stock Exchange-listed Longwei Petroleum Co., whose U.S. investors include the California state pension fund.

In a 38-page report last week, GeoInvesting published what it said were time-lapse-camera images showing weed-grown train tracks and idle storage terminals at sites in China's Shanxi state that Longwei officials had told investors were handling large volumes of fuel in trucks and trains.

Longwei Petroleum "stock, in our opinion, is virtually worthless, completely uninvestable, and should be immediately delisted," GeoInvesting's report said.

In reply, Longwei alleged that GeoInvesting committed "errors of facts, misleading speculations, and malicious interpretations of events." But the allegations stung: Trading in the shares stopped and has not resumed, and a string of shareholders filed lawsuits against the firm. Longwei chief financial officer Michael Toups did not reply to messages Wednesday.

David is one of several China stock-watchers and critics featured in an ABC News report scheduled to air Wednesday night. ABC quotes U.S. Securities and Exchange Commission chairperson Mary Schapiro complaining that China Vice Premier Wang Qishan and other senior officials have refused her requests to cooperate on investigating alleged financial fraud by China-based, U.S.-listed companies.

David and partner Majed Soueidan say they employ 15 at GeoInvesting, including investigators in China.

Breaking bread

Bimbo Bakeries USA, the Horsham-based American arm of Mexico's Bimbo bread conglomerate, says it has bought 30 acres in Macungie Township, near Amazon.com's Lehigh Valley warehouse and will spend $75 million building a new bakery there. It will open in 2014.

The plant will "bring more than 100 jobs to the area," but will also apply "significant advantages in baking technology that will make our operations more efficient," Bimbo said in a brief e-mail statement.

What will that mean for Bimbo's Stroehmann bakery in East Norriton Township, and other aging Bimbo-owned plants? Spokesman David Margulies told me the company wouldn't comment.

Americans aren't buying sliced white factory bread or durable baked snack cakes like they used to. Money-losing Hostess, maker of Wonder Bread and Twinkies, shut its bakeries in Philadelphia and other cities last year, idling 19,000 workers nationwide.

Industrial bakers are "still getting squeezed," says Robert Costello, owner of $55 million-asset Costello Asset Management in Huntingdon Valley.

The East Norriton plant is in a great location, Costello said, near the Philadelphia region's major highway junctions. But, he added, such firms as SuperValu's Acme Markets and Lehigh Valley Dairies have consolidated production and distribution out of the Philly area to upstate counties in search of lower labor costs.

Contact Joseph N. DiStefano at 215-854-5194 or JoeD@phillynews.com, or follow on Twitter @PhillyJoeD.