(Bloomberg) -- Cocoa futures tumbled in New York and London, with the market prone to large price swings as fewer and fewer companies can afford rising costs to back their trades.Most Read from BloombergTesla Soars on Tentative Approval for Driving System in ChinaStocks Trade for 390 Minutes a Day. Increasingly, Only 10 MatterYen Sparks Intervention Suspicion After U-Turn From 1990 LowsElliott Built ‘Large’ Stake in Buffett-Favored Sumitomo, Source SaysMusk Makes Surprise China Visit in Search o