Which of the following retirement plans is NOT restricted to contribution limits set by the IRS?

A Roth IRA is a type of individual retirement account that does have contribution limits imposed by the IRS. For 2023, individuals can contribute up to $6,500 ($7,500 if age 50 or older), which restricts the amount that can be contributed annually. This limitation is an essential aspect of the Roth IRA's design, aimed at controlling tax benefits.

401(k) plans are employer-sponsored retirement savings accounts that also have defined contribution limits set by the IRS. For 2023, the contribution limit is $22,500 ($30,000 for those aged 50 and over). This structure ensures that contributions are capped to maintain tax benefits and encourage retirement savings within defined parameters.

Individual Retirement Plans (IRPs), which include traditional IRAs and Roth IRAs, are subject to IRS contribution limits similar to those of IRAs. This characteristic ensures that there are restrictions on how much individuals can contribute annually, in line with IRS regulations aimed at controlling tax advantages.