Interest rates improved the picture for retirement income for workers in their mid-50s, but a volatile market hurt 60-year-olds’ spending power and was flat for 64-year-olds.

That’s according to the BlackRock CoRI Retirement Indexes, designed to provide investors ages 55–74 a daily estimate of the present “price” of $1 of annual retirement income starting at age 65.

The CoRI indexes are composed largely of U.S. government and investment-grade bonds, and incorporate current interest rates, annuity prices, inflation expectations, life expectancy, and other factors into their estimates.

For the interest rate/volatility determination, BlackRock took quarterly projections of investments and income modeled by the Employee Benefit Research Institute (EBRI) that used data on retirement savings in both 401(k)s and IRAs by age, as well as median income from December 31, 2015, and combined that data with the CoRI Indexes to estimate how much income pre-retirees are positioned now to potentially generate from their savings starting at age 65.

The indexes analyzed estimated retirement income for workers at ages 55, 60 and 64, and found that rising interest rates gave those mid-50s workers a boost of 4.41 percent in retirement spending power.

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But the antics of the stock market took a heavier toll on 60-year-olds, cutting their spending power by 6.4 percent. Those closest to retirement, at 64, actually got a tiny boost, the indexes said, at 0.74 percent.

The cost of generating annual income in retirement went down by 4.05 percent for 55-year-olds, 2.14 percent for 60-year-olds and a whopping 7.39 percent for 64-year-olds, thanks to rising long-term interest rates. As of December 31, 2015, the 10-year Treasury yield curve rose 4.6 percent from the end of 2014.

But the median value of savings for older workers fell, according to EBRI’s data, causing a smaller pool of money from which to draw income; both 401(k) and IRA balances suffered.

That means that older pre-retirees will either have to modify their preparations for retirement by “saving more, investing differently or shifting their retirement goals.”