While Congress and the administration focus mostly on the debt limit crisis, the business of K Street has a lot more to do with narrower legislative issues that mean millions — or billions — to an industry’s bottom line.

Take swipe fees.

The ongoing battle between merchants and banks over the cost of paying with debit cards has fueled a healthy spending spree, according to reports filed this week with Congress under the Lobbying Disclosure Act.

The National Retail Federation, whose members include Macy’s Inc. and the Container Store, spent $920,000 on lobbying during this year’s second quarter, up from $690,000 the previous quarter, for a six-month total of $1.6 million.

On the other side of the debate, the American Bankers Association reported spending $2.4 million in the second quarter for a total of $4.4 million for the first half of this year, up slightly from about $4.3 million for the first half of last year.

The retail federation’s chief lobbyist, David French, said part of his group’s increased lobby spending is because of his industry’s fight with the banks.

“The swipe fee issue really has not gone away,” he said. “This is an area where we’re going to continue to be working.”

It wasn’t the only reason that the group has spent more on advocacy, he added. “We’re moving on up,” he said. “We’re putting more resources into public policy work and lobbying.”

Another issue that has gotten a lot of action on K Street is AT&T’s proposed acquisition of T-Mobile. Rival Sprint, which opposes the merger, upped its lobby spending in the second quarter to $1.4 million from $583,000 in the first quarter for a semi-annual total of almost $2 million. For the first half of 2010, Sprint spent about $1.3 million on lobbying, according to its disclosure forms.

T-Mobile, meanwhile, increased its second-quarter spending this year to $1 million from $690,000 in the first quarter. That $1.7 million total for the first half of this year is up from $1.1 million for the first half of last year. And AT&T, often a big K Street spender, reported doling out about $11.7 million on lobbying for the first six months of this year — up from about $9 million spent for the first half of 2010.