Northbrook-based Lou Malnati’s Pizzeria said Wednesday it will fuel expansion plans with an equity investment from BDT Capital Partners, the first time a nonfamily member has taken an ownership share.

Chicago-based BDT would not say how much they would invest into the company. The deal is expected to close in October.

Co-owner Marc Malnati is expected to continue to be fully involved in the business operations and leadership. Marc’s brother, Rick Malnati, is a co-owner but isn’t involved in the company’s daily operations, said Lou Malnati’s spokeswoman Mindy Kaplan.

“We plan to open three to four new locations each year, with one being a full-service restaurant and the others as carryout and delivery locations,” Kaplan said.

Lou Malnati’s is a favorite in the Chicago and suburban region since 1971 and it has already grown to 45 locations in this region.

They also recently opened a location in Phoenix, Arizona, and plan to expand further in that area.

The move to take on equity funding will help the chain’s expansion through BDT’s experience, advice and contacts.

“Serving legendary deep dish pizza in an environment of fun with dedicated people remains our primary goal,” Marc Malnati said in a statement. “Our customers can expect the same quality and excellence in both product and hospitality that they have experienced over the past 46 years, while BDT’s growth capital and valuable support will help our company achieve our long-term objectives.”

BDT’s experience in advising and investing in family businesses will benefit Lou Malnati’s, said Bryon D. Trott, BDT chairman and CEO.

“Lou Malnati’s Pizzeria is an iconic family business with passionate leadership, dedicated employees, a great brand and exceptional products and customer service,” Trott said in a statement. “We look forward to partnering with Marc Malnati and his strong management team to continue to build upon the Malnati legacy and help them grow in Chicago and beyond.”