The Federal reserve's committee decided not to raise its key interest rate Wednesday. This came as no surprise to investors and traders alike as Fed Chair Janet Yellen foreshadowed the decision in a speech in March, noting that the central bank would move "cautiously" in 2016.

Investors were still on edge before the announcement, but more about what hints the Fed would give about its meeting in June. The committee didn't change its tone by much, but dropped hints on its worries and what's holding it back.

Fed's comments:

"Economic activity appears to have slowed," despite job market gains, the Fed said in its statement. It also noted that household spending had "moderated."

This cautious tone and language greatly lowered investors' expectations for a June rate hike. Before the announcement, the market was pricing in about a 31% chance of a rate increase in June. Just minutes after the announcement, expectations immediately dropped to 19%.

The Fed slightly changed its tone about the global economy, saying it's "closely monitoring" global developments. It seemed to indicate that global "risks," that were a huge worry early in the year, are less of a concern now.

The markets response:

The Dow and S&P 500 hit their highest point of the day after the Fed's announcement, but the markets didn't really bounce all that much. The Dow was only up 64 points shortly after the news came out. The S&P 500 was mostly flat. Shortly after the Fed announcement the markets returned to focusing individually on stocks that were due to report earnings.

The Fed appears to be focusing heavily on the U.S. now. GDP numbers that came out Thursday showed that the economy in the first quarter remains very sluggish, gaining less than the 1% analysts had expected.

"The Fed is conscious of the fragility of the underlying financial and economic conditions," says Jeremy Lawson, chief economist at Standard Life Investments. His comments were one of many following the same tone Wednesday after the announcement.

Recent adjustments:

The Fed's committee raised rates in December for the first time in nearly a decade. In December, the Fed estimated it would raise rates four times in 2016. Then at the start of this year, oil prices fell, stocks tanked and China fears amplified.

In March, Janet Yellen and other Fed officials lowered their expectations to two rate hikes in 2016, where they currently stand now. But even two rate increases doesn't look like a certainty now. For one, the 2016 election could adjust the Fed's thinking, although that's a hot button issue amongst analysts. Secondly, the IMF recently described global growth as "fragile". The Fed doesn't want to do anything that will add to the uncertainty. And as other central banks push interest rates down, that may dissuade rate increases going forward.

Bottom line:

The Fed has and will continue to be a main market driver in 2016 so investor's better take note of the tone and positions that Janet Yellen and her crew are looking to take.