Steve Jobs -- Turtleneck Sales SKYROCKET After Death

You'd think Steve Jobs' death would destroy financial markets across the globe -- but TMZ has learned, one commodity has experienced a dramatic upsurge in sales today ... mock turtlenecks.

You'll recall, Jobs famously rocked the high-neck knitwear during his keynote addresses for Apple -- and now, the company that makes his favorite sweaters says Jobs' death has doubled its business.

A rep for the St. Croix clothing brand tells TMZ, as soon as news broke that Jobs had passed, their mock turtlenecks flew off the shelves -- adding, St. Croix has experienced an "almost 100% increase in sales" since yesterday.

And Jobs' contribution to St. Croix hasn't gone unnoticed -- we're told the company is currently planning a memorial for the former CEO, but it hasn't decided exactly how it plans to honor its muse.

The rep says, "We have a great respect for everything he did and we're glad he believed in our American-made product."