It’s never boring these days. Recall that there are times when the S&P 500 goes 100 days or more without making a 1% intraday move. But big moves are the norm nowadays — and they aren’t bullish. Neither is the fact that the many of the worst of the low-quality stocks that are down still down 80%-90% from highs are continuing to spike. Much, probably most, of the recent rally action for those and other downtrodden stocks has resulted from short covering. Short-selling is when people borrow stock from their broker to sell it immediately, hoping to buy it back at a lower price, return it to the lender and pocket the difference. Short covering is when the trader buys the shares to close out a short position. Short-selling got to be very profitable for a month or two when the stock market was tanking in May and June. But, of course, the action brought in too many short-sellers, which made it crowded. That crowd has thinned out in the past couple weeks. Here are five main reasons I expect a “Big Broad Sell-Off” in coming days and weeks: 1. We had an historic Bubble Of All Bubbles that just popped over the past year. I don’t think the odds favor a quick resolution in the midst of a new Federal Reserve/inflation paradigm. 2. Valuations for most of the former high-flyers that have crashed and then bounced are still too high to be good risk/reward for the long-term. 3. Everyone seems to agree that the Fed can and will simply go back to easy money policies in two months or six months or something. I don’t think the Fed/inflation playbook that will work for the next 10 years or longer is the same playbook that has worked for the last 40 years. 4. Crypto’s crash doesn’t seem like to be over, and I don’t think the tech stock market can bottom until crypto finishes washing out. Too many people who own cryptos that are 70% to 95% off their all-time highs from last year are still talking trash to crypto bears and crypto luddites: “You’re so stupid if you can’t understand that my crapcoin is going to go back up to its all-time highs after this latest crypto winter is over.” I have people talking trash to me who have lost tons of money on cryptos that I had warned them to get out of before they crashed. It reminds me of the time when I was leading the state in scoring but my team was 5-17 on the year. 5. I expect a Big Broad Sell-Off because greed seems to be back driving the market action lately. Many of the trashed former high-flyers that were down 90% or more are now up 50% or more from their lows (which means that those stocks are still down 80%-90% from their all-time highs and almost none of them are ever going back to those levels.Selling and ‘shorting’ Stocks are up big since my early summer bullishness about buying stocks during the panicky selling action. I’ve raised some cash since then in my personal account by selling some names completely, such as PayPal PYPL, +2.01% and Alibaba BABA, -0.11%. In the hedge fund, I have been shorting some of the hyped-up, rallied-up solar stocks, including the Invesco Solar ETF TAN, +1.31%. I’m also staying short some of the worst electric vehicle manufacturers, such as Fisker FSR, +3.90%, although I covered some of it just yesterday. I think we’ll look back in two months’ time and say this sort of thing: “How did all those crappy stocks go up so much so quickly this summer?”Rise of Rocket Lab Rocket Lab RKLB, +21.16%,  which I’ve written about many times over the last year here on MarketWatch, had a great quarter, beating the topline estimates by 10%-plus and guiding next quarter up by 10%-plus. In updating its numbers on a price-to-profit (PP) ratio spreadsheet, it’s cheaper today than it was yesterday even with Friday’s 20% pop in the stock, because adding 10% to the current year’s estimates magnifies profitability in the future years. I’m mostly sitting tight with this name. I wouldn’t go selling a bunch of your long-term stocks or try to game a potential market downturn. We did some buying at those lows that are far away right now and there’s no reason to feel rushed to make your next long-term move. Easy does it, as always. Cody Willard is a columnist for MarketWatch and editor of the Revolution Investing newsletter. Willard or his investment firm may own, or plan to own, securities mentioned in this column.