People who enrolled in health insurance plans through the New York State of Health Marketplace are receiving letters from their insurance companies, notifying them of a proposed rate change beginning in 2015.

Some plans are asking for as much as a 21 percent increase, according to ACR Health.

ACR stands for AIDS Community Resources, "a not-for-profit, community-based organization providing a range of support services to individuals with chronic diseases, including HIV/AIDS, diabetes, heart disease, obesity, asthma, substance use disorders, and serious mental illnesses," their website says.

These letters are required by New York state insurance law. Every year health plans seek to increase rates, ACR Health says.

These letters show the list price of a plan and do not take into account the tax credits and cost sharing reductions the marketplace offers.

While an insurance company may be asking for a rate increase, it does not mean that they will get it. All requests are reviewed by the NYS Department of Financial Services. They may approve or modify the rate change requested by your health plan, ACR Health said.

Any rate increases will not take effect until 2015.