Big shifts in the stock market had clients — and, therefore, real estate agents and brokers — worried yesterday. Oil dropped to its lowest price point since 2003 (below $27 a barrel), and stock sell-offs around the world led to some wild fluctuations.

So what’s it mean, and what should you tell clients?

1. Try not to think about the stock market — or even to look at it. Not until you’re going to retire and need to see how much money you’ve got.

2. The stock market is the most-talked about market (even more than real estate), but it’s the least predictable of all financial markets. We’ve got P/E ratios, Dow Theory, Modern Portfolio Theory (MPT), value investing, momentum, options, Tobin’s Q, quants … if any of it were truly predictive, we’d have known a long time ago.

3. Stock markets everywhere lurch all over the place, sometimes for no apparent reason. Very often for imaginary reasons. If a Realtor looks worried, she or he may create client fear where there was little or none.

4. There is a “wealth effect” by which rising stock markets add “oomph” to the economy, and sinking stocks can slow it, but we need big and sustained moves — think at least 20 percent to begin with. The U.S. move so far has not reached 10 percent.

5. It’s painful to lose a lot of money in a hurry, but stocks are a long-term deal (see “retirement” above). Stocks out-perform every other financial investment (except well-chosen real estate), but that performance comes with a price: truly wild up-and-down volatility.

We must be in the game to win, but the game will drive us crazy if we expect steady gains. That’s what bonds are for, but they are boring and pay poorly.

6. Stocks are a “reversion to mean” game. Stocks tend to go up over long periods, but wander back and forth across the upward-tilted mean.

By the way, that mean is invisible and changes its upward slope frequently, but does not tell us when or how much. The idea is to invest as often as possible, ride the mean wherever it is and goes, and don’t panic or monkey with it.

7. This global stock sell-off has been very orderly. NOT a “crash.” On October 15, 1987, “Black Monday,” the Dow lost 22.61 percent. On one day.

Here in 2016, few markets have lost as much as 3 percent in a day.

8. The Fed intervened in ’87 as it should have, not to support the market but to support the banking system and economy. Not now.

9. The Fed from 2008 to 2013 supported banks and the economy and stocks via “quantitative easing,” QE. Bernanke told us that he intended to support financial assets, to prevent a repeat of 1929-1932. Some of us listened and some did not. Some got a free ride, some missed it.

The Fed raised the cost of money in December for the first time since 2006, in part to see if cheap and plentiful Fed money had created any bubbles. Sometimes the Fed walks into its nice, spotless kitchen in the middle of the night for a snack, flips on the lights, and … ROACHES!!

This sell-off feels like that. Stocks had an effortless run up in the last several years, few “corrections” worthy of the name, and it looks as though the Fed’s dinky move in December alarmed the complacent, who thought the Fed would be easy forever.

10. In addition to the Fed, the most likely catalyst for this sell-off is the increasingly inept thrashing by China. There is a small chance that damage to outsiders can get out of control, and the stock market is a symptom of deeper international distress. Could be.

The U.S. is more protected from international trouble than any nation, but if you’d like something to worry about, there it is. China.

Lou Barnes is a mortgage broker based in Boulder, Colorado. He can be reached at