Ernst & Young and Deloitte Touche Tohmatsu both recorded higher revenue for the past fiscal year, allowing them to plan for further investments in services and technologies for clients.

EY’s revenue climbed to $39.96 billion for the fiscal year ended June 30, up 7.3% from the previous year, the company said Wednesday. Deloitte, its larger rival, on Wednesday reported that revenue rose 5.5% to $50.2 billion during the fiscal year ended May 31. Deloitte is a sponsor of CFO Journal.

EY and Deloitte are the first two among the Big Four accounting firms—which also include KPMG and PricewaterhouseCoopers—to disclose revenue figures for the 2021 fiscal year. The Big Four don’t report their profits due to their status as international networks of private partnerships.

The firms in recent years have been trying to boost their employees’ skill sets and their technological offerings, advising corporate clients, for example, on how to strengthen their supply chain and operate more efficiently. “The Big Four have been at the forefront of trying to apply whatever software and hardware technologies are available,” said Shyam Sunder, professor emeritus of accounting and economics at Yale University.

The business of the four firms generally revolves around the same kinds of services, including audit, consulting and tax advisory and transactions.

EY has four divisions: audit, consulting, strategy and transactions and tax. Audit, its biggest business, generated 33.95% of total revenue, compared with 34.4% in the prior year. Consulting brought in 27.9% of revenue, while tax generated 26.2% of revenue. The strategy and transactions business is EY’s smallest, representing about 12% of revenue. Audit as a proportion of total revenue has shrunk since at least 2010.

Audit revenue, nevertheless, rose by 5.8% to $13.57 billion during the most recent fiscal year. The consulting division recorded $11.14 billion in revenue, up 6.4%. Revenue in the tax business line was $10.47 billion, up 7.2%. Transaction and strategy’s revenue climbed 14.6% to $4.79 billion.

“We are very much bullish on our audit practice and we expect it to grow,” said Carmine Di Sibio, EY’s global chairman.

Deloitte has five divisions: audit, consulting, financial advisory, risk advisory as well as tax and legal. Audit revenue climbed 6.1% to $10.5 billion, while consulting revenue grew 5.1% to $20.8 billion. Revenue in the financial advisory division rose 13.2% to $4.3 billion, while revenue generated by the risk advisory unit went up by 5.4% to $5.9 billion. Revenue booked by the tax and legal business increased 2.3% to $8.9 billion.

Deloitte’s audit revenue comprised 20.9% of total revenue, up from 20.8%. The consulting and advisory arms represented nearly 62%, while tax and legal made up roughly 18%.

Deloitte, which said it invested about 3.5% of its annual revenue—or $1.76 billion, declined to provide specifics about its future spending plans. The firm, which employed 345,374 people at the end of its latest fiscal year, said it continues to invest “hundreds of millions of dollars” in innovating its audit business.

EY over the next three years wants to spend $10 billion on its business. The funds will be allocated toward growing its workforce, buying and developing technology and improving audit quality, in part by creating about 30,000 new jobs annually through 2024. The firm had a head count of 312,250 as of June 30.

EY is improving its training and audit procedures to detect potential accounting fraud following last year’s scandal around German payments firm Wirecard AG, Mr. Di Sibio said. The company in June 2020 disclosed a $2 billion accounting hole, which spurred various investigations into the firm and EY, its auditor.

Mr. Di Sibio said he doesn’t expect the scandal to hamper EY’s ability to win new audit clients in Germany. “The only audits that we’ve lost are companies that had direct investments in Wirecard,” he said.

Separately, Deloitte last year agreed to pay a £15 million fine, equivalent to $20.8 million, to settle charges over failures in its audit of software firm Autonomy Corp.

Write to Mark Maurer at mark.maurer@wsj.com