The Big Four consulting firms are embedded in Big Tech. Here's who audits each of the Magnificent 7 companies.

• The tech giants that comprise the Magnificent Seven now have a combined market value exceeding $20 trillion.
• Who is checking their financial records?
• A group of industry-leading titans, also categorized by a number: the Big Four.

Apple, Microsoft, Alphabet, Amazon, Nvidia, Meta, and Tesla, known as the Magnificent Seven, now have a combined market value of over $20 trillion, making them among the most powerful companies in history.

Who is handling their financial records?

Another numerically-termed group of powerhouses.

The Big Four professional services firms — PwC, Deloitte, EY, and KPMG — are the industry-leading consulting and accounting firms that audit the Magnificent Seven.

Behind the sky-high valuations and global dominance, the Big Four firms independently assess how these companies report their finances, run internal controls, and follow the rules. Audits are a crucial mechanism for ensuring accountability to shareholders, regulators like the SEC, and other stakeholders.

The Big Four are also becoming increasingly embedded in the tech sector itself as they work to provide clients with AI. Deloitte has partnerships with Apple, Alphabet, Microsoft, and Nvidia. While EY has key relationships with Microsoft and Nvidia.

Here's who from the Four audits the Seven.

Microsoft

Deloitte is Microsoft's auditor, the company states on its website.

Shareholders ratify the appointment of Microsoft's auditor annually at the annual shareholder meeting. Under SEC rules, Microsoft's outside auditor is required to regularly rotate the key audit partner, at least every five years.

Deloitte, the largest of the Big Four by revenue and employee numbers, has been Microsoft's public auditor since its IPO in 1986, according to a statement from its annual shareholder meeting.

Microsoft paid Deloitte $78.4 million for audit and other services in its 2025 fiscal year, which ended on June 30, the statement shows.

As 2025 comes to a close, Microsoft is valued at $3.61 trillion, and the company's stock is up 15% year-to-date.

Apple

EY serves as Apple's auditor and has done so since 2009, according to Apple's 10-K filing for the fiscal year ended September 27, 2025.

In 2024, Apple paid EY $30 million in fees for the year ending September 28, 2024, up from $25 million the year before.

Apple is valued at roughly $4 trillion, and its stock has increased by 9% year-to-date.

Alphabet

Alphabet, the parent company of Google, is audited by EY, according to its statement following the 2025 Annual Meeting of Stockholders.

Alphabet paid EY $6.5 million in fees for auditing and other professional services across its 2024 fiscal year, the statement shows. The previous year, the fees were $41 million.

Alphabet, under the leadership of CEO Sundar Pichai, is valued at $3.7 trillion, and its stock is up 62% year-to-date.

Amazon

Jeff Bezos's Amazon empire is also audited by EY.

"We have served as the Company's auditor since 1996," a note in Amazon's annual shareholder meeting statement said.

Amazon spent $51 million with EY in audit fees for its 2024 fiscal year, the statement shows.

In late 2025, the company is valued at $2.43 trillion, but Amazon's stock has been lagging behind the rest of the Magnificent Seven over the last five years.

Nvidia

AI juggernaut Nvidia, is being audited by PwC for its 2026 fiscal year, ending January 31, 2026, according to the Nvidia Corporation Annual Review.

PwC has audited Nvidia since 2004, the report notes.

Nvidia has been around for over three decades, but in 2025, the chipmaker became the first company to hit a $4 trillion market cap.

Nvidia lists a $10 million spend with PwC for audit and other professional services in its 2025 fiscal year, up $1 million compared to the year before, the review shows.

Meta

Meta, which owns Facebook, is the fourth member of the Magnificent Seven that turns to EY for its annual audits.

Meta shareholders ratified the appointment of EY as the company's public accounting firm for the fiscal year ending December 31, 2025, as stated in a recent 10-K filing.

Meta listed fees of $36.3 million for auditing services in the company's 2024 fiscal year.

The firm has been Meta's auditor in the US since 2007. The company is worth $1.66 trillion, and Meta's stock is up 12.5% year-to-date.

Tesla

Elon Musk's EV company, Tesla, is audited by PwC, according to SEC filings. The Big Four firm has audited Tesla since 2005.

Tesla has had a turbulent year, with Musk's political involvement sparking backlash against the automaker. Early in the year, protesters against his involvement with the Trump administration gathered at Tesla dealerships, with some burning cars.

The company's stock has made a significant comeback since its challenging opening quarter saw shares nearly cut in half. Tesla stock is now up 19% as 2025 draws to a close, and it is valued at $1.6 trillion.