Interesting that in both cases, #13 and #18, the culprit for this little piece of writerly self-indulgence was the Economist. There are a few other examples (all BE? #14), but I don't think this supposed financial sense is very likely to catch on widely elsewhere, because it forces the reader to puzzle out why the word was used. 'Um drei Ecken denken' isn't really very clear journalistic style.
In fact, our usual associations with frothy -- foamy, bubbly, light, entertaining, beer, champagne, cheerful, tasty, mindless entertainment, etc. -- are actually out of place here. The word is generally positive, whereas the intended meaning in this rather twisted sense is not. So I wouldn't advocate imitating this usage.