Big banks like JPMorgan Chase & Co. (JPM) - Get Report and Bank of America Corp. (BAC) - Get Report are happy to take money from people who will give it to them for free. 

But there are plenty of other banks, including Ally Financial Inc. (ALLY) - Get Report and even the Wall Street firm Goldman Sachs Group Inc. (GS) - Get Report , who will actually pay depositors for the cash -- with decent interest rates.

A basic Chase savings account at JPMorgan currently offers an interest rate of 0.01%, according to the New York-based bank's website. That's essentially the same as in 2015, before the Federal Reserve started a three-year-long campaign to raise interest rates that has since brought them from near zero to a range between 2.25% and 2.5%. And while JPMorgan has used the opportunity to charge higher rates to borrowers on credit cards, mortgages and business loans, it has shared virtually none of that benefit with regular savers. 

An online savings account at Goldman Sachs, meanwhile, pays 2.25%, the third-highest rate in the U.S. for a minimum $1 deposit, according to industry tracker Bankrate. To customers with small accounts, the difference may not matter much. But for a $10,000 deposit, it works out to an extra $224 a year -- enough for a few nice meals or nine $25 gifts for friends and relatives.

For bank-stock investors, the dynamic is crucial to understand. Most traders now believe that the Federal Reserve is likely this year to pause its rate-hiking campaign, which means banks might now find it harder to jack up rates on loans. But savers are still free to shop around for a better deal. 

And that means the big banks might have to start paying higher rates on deposits to keep customers from defecting to smaller banks with better offers, or to online-only lenders that don't have to cover the costs of maintaining hundreds or thousands of branches.        

"Even if the Fed pauses, the deposit rates are going to reprice upward, and that puts pressure on margins," said David Hendler, principal at the bank-analysis firm Viola Risk Advisors in Montebello, New York. 

After falling an average 20% last year, large-bank stocks are up about 13% so far in 2019. But according to a report last week from Standard & Poor's, the year ahead isn't looking so sanguine for banks, partly because of heightened competition for deposits.

"It's still sunny, but the good times may be behind us," the credit-rating firm wrote Jan. 16. 

Take a look at what's happened over the past few years to JPMorgan's "deposit margin" -- essentially the difference between the average interest rate the bank charges on loans, and what it pays out on deposits. In 2015, the margin was 1.9%; last year, it rose to 2.38%.

JPMorgan also landed a windfall from President Donald Trump's corporate tax cuts last year, and net income surged by 33% to a record $32.5 billion. The bank's 62-year-old CEO, Jamie Dimon, got a $29.5 million bonus for 2018, on top of his $1.5 million salary, for total annual compensation of $31 million, or a 5% pay raise. 

That's how it goes when a team of savvy bank executives successfully stacks up billions of dollars in tax savings alongside tall piles of $224's -- instead of sharing the bounty with loyal customers. 

Fortunately for savers, the competitive pressures on banks are starting to mount, forcing them to increase deposit rates.

During the last three months of 2018, the national average for a savings account at a brick-and-mortar bank branch rose by 0.02 percentage point, according to the brokerage firm Keefe, Bruyette & Woods. It may not sound like much, but that's double the increase witnessed in the third quarter. The national average for a one-year certificate of deposit rose by 0.17 percentage point, accelerating from the third quarter's 0.14 percentage-point increase.

According to a study last November by the management consultancy cg42, "not offering competitive rates" ranked as a top "frustration" driving customers to change banks, along with "engaging in dishonest, unethical or illegal practices," "being nickeled and dimed with incidental charges" and "having my personal or account information compromised/put at risk." 

There's a lot to choose from. The upshot, according to the study, is that the top 10 retail banks are at risk of losing some $344 billion of deposits as customers switch accounts over the next year, representing $11 billion of forgone revenue. 

Just listen to how bank executives describe the dynamic to their own shareholders -- the very ones who stand to benefit from "not offering competitive rates," as it were.

On a conference call last week with Wall Street analysts, JPMorgan CFO Marianne Lake was asked to disclose the percentage of the Federal Reserve interest-rate increases that are being passed along to savers.

"In checking and savings, at least savings, it's nothing," Lake said on the Jan. 15 call. "In CDs, it's something, but it rounds to a very small number."

During a Bank of America conference call the next day, the ebullience was palpable.

"You've been able to hold deposit pricing very nicely," John McDonald, an analyst at the brokerage firm Sanford Bernstein, told executives, according to a transcript. 

"Look, I think Bank of America and indeed the rest of the industry really haven't increased deposit pricing on traditional bank accounts appreciably," CFO Paul Donofrio replied. 

Cue Mr. Burns from The Simpsons, tenting his fingers. Excellent

Charles Montgomery Burns, owner of the Springfield Nuclear Power Plant in the animated television series The Simpsons.

Donofrio said that customers receive plenty of other benefits from socking their money away in the firm's vaults, including "transparency, convenience, safety, mobile banking, online banking, our nationwide network of financial centers, the rewards we give our clients, the advice and counsel."

"All that value, I think, has helped us keep deposit rates relatively flat in traditional retail accounts," he said. 

In other words, customers get everything but a decent interest rate.

There was a different tone on the Goldman Sachs conference call, where executives a couple years ago started an online bank, Marcus, to collect deposits as a form of corporate funding. (Prior to an emergency move during the financial crisis of 2008, the Wall Street firm wasn't technically a bank, so it didn't offer savings accounts to the general public.)   

Goldman Sachs doesn't have to shoulder the costs of building and maintaining branches or paying tellers and managers, so it can afford to pay a higher rate on deposits than its larger brick-and-mortar competitors.

In terms of the deposit rates offered, "Our objective in the U.S. has always been to be in the top two, three or four" nationally, CFO Stephen Scherr said on the Jan. 16 call. 

It almost sounds like he's proud of giving customers a decent deal. 

JPMorgan is a holding in Jim Cramer's Action Alerts portfolio. Want to be alerted before Jim Cramer buys or sells the stock? Learn more now.