They hope these will inspire clients and employees, who are offered twilight tours, lectures and studio visits.
"They want to convey the impression to clients, customers, but also to their employees, that this is an attractive place to work," said Colin Tweedy, head of creative network Arts & Business.
"Solid rows of computer screens is not a good way of getting the best out of people."
Deutsche Bank - whose works include striking sketches by Kitaj and an arresting Francis Bacon lithograph based on his portrait of Pope Innocent X - spends an average of under 1,000 pounds per item for its collection of post-1960 works on paper.
Even then, every purchase is vetted by an art committee.
"It is not a museum we are buying for, it is an active business," said Alistair Hicks, art adviser at the bank.
O'Day added: "They don't necessarily see it as an investment. It's an investment in terms of bringing energy into the building and making people look - and look twice."
But the daring approach can help firms attract clients as wider interest in art investment grows.
And in a downturn, more restrained spending allows most companies to keep their initiatives going - though they walk a delicate line as jobs are cut and budgets shrink.
Collectors, curators and advisers alike say the market is unlikely to remain immune to a faltering economy, as many major corporate commissions are linked to property moves such as new headquarters or big projects like Heathrow's Terminal 5, which includes a large commission by artists Langlands & Bell.
But most have yet to feel the impact. And the credit crunch will not kill the taste for art.
"Obviously they are not going to go on a massive spending spree," said Tweedy. "If you are laying off large numbers of staff the last thing you want to do is be seen to be spending your money unwisely.
"But no-one now (tells) a bank, or any business, that engaging in the arts is a 'waste of money' or 'corporate theft', as it would have been called in the Thatcher years. It is simply good business, and the employees like it."
But budgets will tighten further.
"We are not in an ivory tower," said Deutsche Bank's Hicks.
"When it comes to arguing our case for our budget, if markets are tough we are less likely to succeed. But if the market is down, we can also buy more for the same money."
