Two longtime Charleston accounting businesses will merge with a regional firm from the Upstate next month, marking more consolidation within the tax advisory industry.

McKnight Frampton CPAs LLC and Schleeter Monsen & Debacker LLP are combining their operations with the larger Greenville-based Elliott Davis LLC.

Terms were not disclosed.

The Charleston certified public accounting firms will begin operating under the Elliott Davis name Jan. 1.

"We are proud to join together with two of Charleston's most experienced and highly regarded firms so that we may provide a broader range of accounting and business advisory services to the Charleston area," said Todd Mitchell, chairman of Elliott Davis.

Schleeter Monsen & Debacker was established in 1919, and McKnight Frampton CPAs followed suit in 1934. Together they have 40 employees, increasing Elliott Davis' payroll to 375 workers.

Mitchell said Elliott Davis "has developed a rapidly growing practice" in the Charleston region in recent years. The merger will allow the firm to "offer services to these clients from a local base," he said.

McKnight Frampton and Schleeter Monsen & Debacker will continue to operate from their existing offices in downtown Charleston, but they plan to combine the locations in the future. Both said they will be able to offer their clients more services by combining with a larger firm.

Elliott Davis, which traces it roots to 1925, is a regional tax and advisory business with nine offices in the Carolinas, Georgia and Virginia before the Charleston deal. It also operates several subsidiaries, including affiliates that specialize in investment banking, retirement planning, technology and wealth management.

The Upstate firm is setting up shop in Charleston two months after opening its first Myrtle Beach office and about a year after two of the Lowcountry's largest independent accounting firms — Gamble Givens & Moody LLC and Pratt-Thomas & Gumb CPAs — joined forces with Asheville, N.C.-based Dixon Hughes PLLC.