The phrase "a relatively high interest" is correct and usable in written English.
It can be used when discussing levels of interest that are higher than average but not excessively so, often in contexts like finance, research, or general discussions about preferences.
Example: "The survey revealed a relatively high interest in renewable energy sources among the participants."
Alternatives: "a considerable interest" or "a significant interest".
"But who we see targeted is the vulnerable senior, the widow living on Social Security who has outstanding credit-card debt at a relatively high interest rate".
Some say no matter how unsophisticated they were, they should have known better, especially when they were offered such a relatively high interest rate.
For a start, the government is likely to pay a relatively high interest rate on the bonds it now plans to issue (and sell to Hugo Chávez's Venezuela, its new ally).
Of those who expressed a relatively high interest in a plug-in car, only 22 percent were interested in a pure electric car, while 78 percent expressed interest in a plug-in hybrid.
You earn a relatively high interest rate on your deposits, a number negotiated between labor and management.
Online- and mobile-only banking can offer you limited fees, low or no minimum account balances and a relatively high interest rate on your savings.
We still have a relatively high interest-rate structure, although not much different from Australia's.
So the government has to offer a relatively higher interest rate to attract investors, thus increasing its overall borrowing costs.
Considered something of a risk, she took out a mortgage with relatively high interest rates that he likened to today's subprime loans.
The story they tell is that expectations of a rising krona, combined with relatively high interest rates, drew hot money in via the carry trade.
By combining high credit quality (because certain borrowers are not eligible for cheap loans because of the imperfections of the regulatory system) and relatively high interest rates, alternative lending is a very interesting asset class for investors.
