Rating agency S&P gave Turkey a thumbs-up, lowering its long-term foreign currency rating to "B" from "B+". This pushes Turkey deeper into the junk zone, where investments are considered highly speculative.
The American agency announced that the outlook was stable.
Reasons for the step include high inflation and the currency crisis in the country.
According to official figures, the rate of inflation has meanwhile reached 80 percent, and there seems to be no improvement in sight.
At the same time, the Turkish lira has lost enormous value against the dollar and the euro in recent months.