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Comment by pavel_lishin | Hacker News Reader

> COBOL is 65% of active code used today; and runs 85% of all business transactions.

That... just doesn't feel plausible to me. I might believe the second half of that sentence, but I don't think I believe the first.

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I completely believe it. The critical paths in critical software operated by every major company or governmental entity that you deal with were written in COBOL/Fortran/Progress and run on IBM mainframes (hence why they are still a tech titan and will probably remain so for the foreseeable future). And they aren't moving away any time soon because they are too important to fail.

Things that are largely or entirely done on mainframes today:

- Airlines: ticket reservations, crew management, route planning, critical flight operations, some parts of traffic control

- Banking: money movement, loan origination (though some of this has moved off over the years), account management (most of the slick frontends you use on the daily are just wrappers around mainframe programs)

- Government: So much state government stuff (licenses/registrations, tax systems)

I haven't personally done a lot of work on the mainframe, but as I understand it, they are still unbelievably robust machines that are extremely redundant and reliable and still have unmatched uptime guarantees.

Many of these claims about COBOL originate from reports which are decades old. I sometimes hear a stat that 5 billion new lines of COBOL are written per year. When I looked into this claim, it turned out that it originated from a Gartner report written in the 90s.

And they do not link out to anything that even remotely validates this

> Various recently published COBOL articles state the following…

For all we know those articles could be LLM written blogpost spam that just happens to support what the authors of a COBOL consulting firm want us to believe

Mainframes are king on Wall Street and any company dealing with extremely high volume of transactions. They are hardware optimized to process millions (billions?) txns per second. Nothing yet can still compete. The main language for Mainframes is COBOL.

Replacing just any failed hardware component does require downtime, that is critical for any financial business.

So he number does not surprise me.

Many companies tried to move off mainframes, but they realized the costs and risks are to great to bet their business in order to be "cool".

I am absolutely certain that there is a huge amount of COBOL code underpinning financial transactions, but the 65% and 85% numbers seem suspicious to me in 2025.

But can it do HFT?

The information and the statistics on the page have been the same since at least 2014 (when the first instance was recorded in the Internet Archive).

You're right, I wonder how they calculated that number...

I can’t prove it but it sounds like complete bs. How is “active code” even measured?

>We offer experienced COBOL (and other software) consultants

Hmmm

Imagining an exec coming across this article in 2025 and talking about COBOL like they are currently talking about AI.

"Hey X, can you check with the IT guys how much COBOL we are using and how that number can be increased? Thx"

Maybe this is today. Because, you know, AWS is down.

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