NEW YORK (CNN/Money) - Over the past few years, the stock and Treasury markets have been at loggerheads. When investors felt good about the economy, share prices went up and bonds headed down. But when greed gave way to fear they rushed right out of stocks into the safety of bonds.

It's made it hard to remember that for years and years stocks and Treasurys ran hand in hand with one another.

The inflationary 1970s were bad for the Treasury and stock market alike. But as disinflation began to take hold in the early 80s, Treasurys began to rally -- pushing their yields ever lower -- and stocks followed shortly after. It was happy times for both markets until 1999, when the Treasurys ran into trouble, but stocks just kept heading higher.

Justin Lahart, senior writer at CNN/Money, talks about the relinking of Treasury markets and stocks. Play video (Real or Windows Media)

Bond investors, it seemed were worried that the economy was getting overheated, but equity investors thought that was nonsense. The Lehman Brothers Long-term Treasury index dropped 8.7 percent and the S&P 500 added 19.5 percent. Meanwhile, the Nasdaq jumped 85.6 percent.

Not paying attention to the Treasury market was something that equity investors would pay dearly for. In 2000 the stock market cracked, and money rushed into bonds.

But now, after so many years in each other's doghouse, the bond and stock markets may be in the process of relinking. The sharp selloff in Treasurys that began in June is beginning to wear at stock investors nerves. On both Monday and Tuesday, both markets fell. Yes, the drop in Treasurys suggests a recovering economy, but the attendant rise in interest rates may, investors worry, sap the recovery's strength.

Meanwhile, higher yields are making the Treasury market more attractive, and some investors may begin to shift some assets out of stocks to take advantage of that.

The upshot? It may be that the stock market will make no significant headway, and may even fall, until the Treasury market stabilizes.