Foreign investors continue to desert South Africa’s bond market in July, with their share of government debt falling to the lowest level in more than eight years.

Non-resident bond holdings fell to 30.1% as of July 31, from 30.6% the previous month and as high as 37.3% in January, according to National Treasury data. Foreigners have sold a net 54 billion rand ($3.1 billion) of the debt this year, JSE Ltd. data show.

South Africa lost its last investment-grade credit rating in March, when Moody’s Investors Service cut its assessment to Ba1 from Baa3. S&P Global Ratings and Fitch Ratings downgraded the country deeper into junk. The bonds exited indexes tracking investment-rated debt, sparking forced sales by funds benchmarked against those.

“The continuous downgrades by all three ratings agencies seem to be having the effect of taking South Africa off the radar for many offshore investors despite the attractive yields on offer,” said Deon Kohlmeyer, a Johannesburg-based trader at Rand Merchant Bank. “It remains to be seen whether local investors can take up the issuance slack created by the reduction in offshore investor interest.”

Yields on government bonds are among the highest in emerging markets, with benchmark 10-year debt offering a pickup of 8.78 percentage points over U.S. Treasuries. The 10-year yield rose seven basis points on Tuesday at 9.35%. It’s climbed 71 basis points since the beginning of June.