(This article first appeared on Bloomberg)

Trying to understand what causes flash crashes is no longer just for financial regulators and Wall Street. It’s a big deal in Silicon Valley too.

Since billions of dollars were quickly erased from U.S. stocks in May 2010, the U.S. Securities and Exchange Commission has been trying to create a massive repository that would track stock and options trading from exchanges and broker-dealers on a daily basis. That way regulators could quickly go back and find clues to what caused a market interruption. The lack of progress was highlighted last August when the Dow Jones Industrial Average dropped 1,100 points in the first few minutes of trading, sending regulators scrambling once again to figure out what went wrong.

Technology giants like Google parent Alphabet Inc. and Amazon.com Inc. are jumping at the chance to help build the storage for the exchanges via their cloud services. That’s intensified resistance by Wall Street, since the new database, known as the Consolidated Audit Trail, or CAT, could include personal information such as names and addresses from more than 100 million customer accounts. Brokers and banks are worried about everything from data breaches to technology firms making one of their biggest inroads yet into the financial world.

“This is a huge opportunity for Amazon and Google,” said Jo Ann Barefoot, a senior fellow at Harvard University who studies fintech and a former official at the Office of the Comptroller of the Currency. “Their involvement in this project I do think is a threat to the incumbents. If big tech firms can win more trust in Washington, that’s one of the biggest challenges facing banks.”

Big Data

Data is playing an increasingly important role in the financial services industry as services such as lending and managing money become more reliant on analyzing market trends. The big data market for financial services is expected to increase to $53.4 billion in 2017 from $32.1 billion in 2015, according to a report by PricewaterhouseCoopers.

Right now if the SEC wants trading information it can take days. That’s because it often has to cobble it together from different systems run by the exchanges and Wall Street-funded overseer, the Financial Industry Regulatory Authority. Under the CAT system, regulators would be able to see data from the previous day’s orders by noon the following day.

That information could be stored in a cloud, where it would be encrypted and the SEC would be able to access it remotely, rather than on in-house servers. Amazon and Google’s cloud businesses already keep data for other companies, including rivals, without providing the tech firms with access to it. The agency declined to comment on the teams bidding to run CAT.

“We think CAT will certainly facilitate our ability to do our job,” Steve Luparello, the SEC’s director of the division of trading and markets, said in an interview. “As the August event of 2015 pointed out, we have access to all the data we need, but it’s labor-intensive and time-consuming to aggregate all that data and begin that analysis.”

Luparello said the SEC expects the initial phase of CAT, which will include stock and options data collected from the exchanges and Finra, but not order information from broker-dealers, will be operational by the end of next year.

‘Treasure Trove’

Lobbying by industry trade groups has mounted, with the Securities Industry and Financial Markets Association, which represents the biggest broker-dealers, complaining about potential costs for its members in a July letter to the SEC. The agency has estimated that CAT implementation costs for exchanges and broker-dealers could be about $2.4 billion, while the firms’ expenses for maintaining the records would be about the same at $1.7 billion.

The Investment Company Institute, whose members include some of the biggest asset managers, also sent a letter last month, outlining its security concerns. “This treasure trove of order and execution information has tremendous commercial value, and we are gravely concerned that cyber criminals and others will seek to access and use it for their personal gain to the detriment of funds and their shareholders,” David Blass, general counsel at ICI, wrote in the letter.

Amazon is working with Finra in its bid to build CAT, after the regulator migrated 90 percent of its data, such as brokerage transaction records, to Amazon’s cloud services. Financial technology firm Fidelity National Information Services Inc. has partnered with Google to vie for the contract. Winning would help expand the technology firms’ cloud computing, one of their fastest growing businesses. Building CAT could cost as much as $92 million initially and then $93 million annually for maintenance, according to estimates published in April.

Last month, Amazon said that in the second quarter its cloud-computing division delivered operating income of $718 million — 56 percent of the company’s total, while accounting for only 9.5 percent of revenue. Meanwhile, Alphabet beat analyst estimates last quarter in part due to gains in its cloud-computing business.

No Peeking

Amazon and Google’s potential role in CAT has also stoked fears about what the technology giants’ broader, long-term goals may be in financial services. Some worry that any insight into what could be the world’s largest repository of securities transactions will provide ways for either company to profit beyond cloud services.

Still, the business opportunity for Amazon and Google to provide cloud-computing services is so big that it makes little sense for the companies to risk alienating clients by peeking at their data. Neither company has said it has plans to get involved in the trading business. It’s also specified in the CAT proposal that whoever wins the bid must ensure the security and confidentiality of the data, and agree to use it only for appropriate surveillance and regulatory activities. Spokesmen for the firms declined to comment on their involvement to build CAT.

Werner Vogels, chief technology officer at Amazon, said at an event earlier this month that lower costs and greater security were two of the primary reasons customers shift data from their own servers to Amazon’s.

Finra Recusal

Finra’s move to the cloud cut costs, while also bolstering data security and surveillance capabilities, according to Steve Randich, the regulator’s chief information officer. Firms, banks, broker-dealers and other regulators have asked for information on how Finra outsourced its data storage, he said.

“There is resistance, but it is fading,” said Randich. “You could measure the sentiment change by the week.”