• McKinsey, Bain, and BCG are top strategy consulting firms with low acceptance rates.
• These firms, known as MBB, serve Fortune 500 companies and offer competitive salaries.
• MBB firms provide prestigious exit opportunities, often leading to senior roles in various sectors.

McKinsey & Company, Bain & Company, and Boston Consulting Group — collectively referred to as MBB — are widely considered the top three strategy consulting firms in the world.

Sometimes referred to as the Big Three, MBB firms are among the most prestigious consulting firms and their clients include many Fortune 500 companies as well as government agencies.

CEOs often turn to these firms for their expertise in business strategy and solving complex problems, whether it's handling mergers and acquisitions or budgeting and cutting costs.

Jobs at MBB firms are famously difficult to land and are among the most sought-after positions for MBA students at top schools. The acceptance rates for these firms is less than 1%. Applicants to top business schools are also far more likely to be accepted into MBA programs if they come from an MBB.

MBB firms typically offer highly competitive salaries, generally paying more than other consulting firms, and often come with demanding work responsibilities and expectations.

MBB firms are also well known for the exit opportunities they provide — employees at these firms are highly sought after for other jobs and often end up with senior positions at Fortune 500 companies, startups, hedge funds, and private equity firms, or start their own companies.

The Big Three is sometimes confused with the Big Four, which refers to the professional services firms Deloitte, EY, KPMG, and PwC. The Big Four are the largest accounting firms in the world though they also offer consulting and other services.

The MBB firms are strategy and management consulting firms. Here's how they compare.

McKinsey & Company

McKinsey is typically considered the most prestigious of the Big Three. It's also the oldest and was founded in 1926.

Headquartered in New York City, McKinsey is also the largest of the MBBs, with more than 45,000 employees across 130 offices worldwide.

McKinsey generated around $16 billion in revenue in 2023 and is led by Bob Sternfels, who serves as the firm's global managing partner and chair of the board of directors.

McKinsey told Business Insider it receives more than one million job applications each year and that the company planned to hire about 6,000 people in 2024, about the same as the year prior.

That would mean McKinsey hires around 0.6% of applicants.

McKinsey's average base salary for new hires out of undergrad is $112,000 and for MBAs $192,000, according to the company Management Consulted, which provides students with coaching for consulting interviews.

McKinsey is notorious for its demanding workload, with even entry-level analysts working 12 to 15 hours a day. One former employee told BI that the experience took a toll on her mental health but she came away with confidence and a Rolodex of contacts.

Boston Consulting Group

BCG was founded in Boston, where it is still headquartered, in 1963. The company had 32,000 employees as of 2023 and 128 offices worldwide.

BCG had a global revenue of about $12 billion in 2023.

BCG is led by Christoph Schweizer, who has served as CEO since 2021, and Rich Lesser, the Global Chair of the firm.

BCG's head of talent, Amber Grewal, told BI more than one million people apply to work at the company each year and that only 1% make the cut.

Amid the boom in generative AI the firm is hiring for a wider mix of roles than it did in years past. "It's going to change the mix of people and expertise that we need," Alicia Pittman, BCG's global people team chair previously told BI.

The average base salary at BCG for hires out of undergrad was $110,000 in 2023 and about $190,000 for MBAs and PhDs, according to Management Consulted.

Bain & Company

Bain was founded in 1973 and is also headquartered in Boston.

The smallest of the Big Three, Bain has around 19,000 employees with offices in 65 cities around the world.

Bain's revenue in 2023 reached $6 billion, according to the Financial Times.

Bain is helmed by Christophe De Vusser, who serves as the worldwide managing partner and CEO.

Bain's average base salary for undergrads in the US is around $90,000, while for new hires with an MBA or PhD it was around $165,000, according to Management Consulted.

Despite the grueling hours and high expectations, Bain is known for a collaborative culture.

"We have a motto, 'A Bainie never lets another Bainie fail,'" Davis Nguyen, a former consultant at the firm, previously told BI. "We all work together from entry-level associate consultants to senior partners. I think that is what makes Bain's culture what it is — that we all work together to achieve a goal and make everyone around us better."

Bain is also considered the "frattiest" of the top firms and is known for a "work hard, play hard" culture, according to Management Consulted.