Utilize your financial knowledge, give your answer or opinion to the input question or subject . Answer format is not limited.

Why don't banks give access to all your transaction activity?
All the other answers here are correct, but I'll add one more perspective. I am a business architect at one of the world's largest retail banks. Every day I experience the frustration of trying to get large-scale corporate IT to do anything, so I feel that your question is just one facet of the wider question: "why are banks so old and busted?" While it's true that the cost of online, redundant, performant, secure data storage is significantly higher than you anticipate in the question, it should still be well within the capacity of a large enterprise. The true cost is the cost of change. Nothing at a bank is a green field development. Everything is a bolt-on to existing systems. Any change brings the risk that existing functionality will be affected, therefore vast schemes of regression testing (largely manually executed) spring up around even the most trivial developments. Costs scale exponentially with the number of platforms affected (often utterly distinct, decades-old, incompatible platforms that have arisen out of historical mergers and acquisitions). Only statutory, revenue-generating and critical maintenance change is approved. Any form of cost-cutting that increases risk is quickly extinguished. This is because when things go wrong, IT get blamed by their business colleagues. This is because the business colleagues in turn get blamed by the regulators, the media, the customers, and the public at large. Who doesn't cuss their bank when the ATM is unavailable? The bank's IT organization develops a kind of management sclerosis, risk averse in the extreme. Banks can't ship a beta version and patch it later. This ultra-low-innovation approach is a direct result of market and regulatory forces. If you were happy with a bank account that played fast and loose with your money the way Facebook plays with your data, then banking would be much cheaper, much more innovative, and much riskier. To get back to your specific question, some banks actually do offer a much longer back catalog of transactions for download (usually only a few key fields of each transaction though), and the ones that don't most likely don't see it as a revenue generating selling point, and it therefore falls above their innovation appetite.