Cuck Bernie has no chance against alpha male Trump (not insults, pure descriptions). He's more ripe for lampooning than Low Energy Jeb. The stock market should price in zero chance that Bernie will win.
IF he could win the dem nomination and pulled ahead in Trump vs Bernie polls AND he doesn't die of old age in the next 6 months, the market would start pricing in his win by crashing. In general I think the market will view anyone non-Trump very negatively; Trump is enormously pro-business and anti-regulation which has meant an economic boom and small business confidence.
There's hard proof of this: here's small business confidence when Trump was elected. It soared over pre-GFC levels for the first time since the GFC, after languishing for a decade. It has stayed elevated as well.
There are a lot of data that small business confidence translates into jobs, investment, economic growth and wage growth. Hate Trump all you want (like a crazy person) but he's responsible for a good part if not all of the economic boom we've had since he was elected, and the stock market run. I think the market sees it that way too.