If this correction turns into a bear market, all bets are off. The S&P 500 won't regain its February high until July 2027.

The S&P 500 SPX will bottom on May 17 at 5,309 - 13.6% below its Feb. 19 all-time high. That's if the U.S. stock-market correction that we now know began on Feb. 19 lasts as long as the median correction of the past 100 years, and declines just as much.

Of course, the current correction could morph into a major bear market if the market loses more than 20% from its high. But odds are that it won't. Of all S&P 500 drops of at least 10% since 1928, 60% of them stopped before the market fell through the 20% threshold to satisfy the semiofficial definition of a bear market.

Whether these odds are comforting depends on your perspective. On the one hand, you may be discouraged to learn that there are two more months of losses ahead for just a garden-variety correction. On the other hand, since the S&P 500 drops 13.6% in a median correction, that means most of the price damage is already behind us. The market would need to drop only 3.9% more from Thursday's close to be 13.6% below its February high.

Your next question might be what history says will be the length of the market's recovery from the correction. Again, on the assumption that this correction will be of the median length and severity, it will take almost four months from the correction's bottom - until Sept. 11, to be exact-for the S&P 500 to recover and make it back to new high territory.

The statistics reported here, based on data back to the 1920s, tell a slightly different story than what you may read elsewhere. My MarketWatch colleague Isabel Wang, for example, recently reported what the typical correction looks like based on data since 2008.

Peering into past corrections

Bear in mind that the median, which is the basis of the conclusions reported here, glosses over a range of lengths and losses of history's actual corrections. As you can see from the table below, some corrections cause the market to decline by the most it possibly can without becoming a bear market - while others are virtually over the moment the market drops into correction territory. There is also a wide dispersion in correction lengths.

About those bear markets

To repeat, the data reported so far in this column depend on the assumption that this is a correction rather than the beginning of a bear market. What does history tell us to expect if indeed this correction does become a bear market?

The picture isn't pretty. The median bear market lasts 261 days and involves a peak-to-trough loss in the S&P 500 of 32.7%. If we're in a median bear market, therefore, the market's decline will last until Nov. 7 and the S&P 500 will drop by 25.1% more than it has already. And, again assuming we're in a median bear market, the S&P 500 will need more than a year thereafter to fully recover the ground it lost in the bear market - not reaching a new all-time high until July 25, 2027.