When President Obama signed the Senate health care bill Tuesday, the mood among beat reporters resembled the last day of finals in college: pride in the long, hard hours they had put in; wonder about what they would do next; and relief that finally it was over.

But on K Street and in the business world, folks knew better. It's not over.

Far from it. Health care reform means it's always Christmas on K Street.

If you think Pfizer, General Electric and the American Medical Association do a lot of lobbying now (and they do), wait until this bill's health insurance "exchanges" are established and Uncle Sam starts laying the ground rules for what is and isn't covered and subsidized.

Under Obamacare, the Office of Management and Budget, which will govern the exchanges regulating and subsidizing health insurance, will hold the purse strings of companies that make drugs, mammogram machines and MRIs.

Hudson Institute fellow Tevi Troy, an alumnus of George W. Bush's Health and Human Services Department, made the point on these pages Wednesday: "the shape of the new law will not become clear once the bill passes and is signed. The administration and personnel in charge of the implementation will have a great deal to do with the final structure of the new law."

And the regulations implementing the law will not be crafted in a hermetically sealed chamber. The bureaucrats, by necessity, will take comments and suggestions from those who best understand the markets to be regulated -- and that will include lobbyists from health care companies.

The drawn-out implementation period -- some provisions don't go into effect until 2018 -- gives plenty of time for stakeholders to make their case to HHS, OMB, Treasury and the Internal Revenue Service.

And, then, of course, there's Congress. What do you think the politicians mean when they call these two bills "a good first step." They mean they're coming back for more -- more subsidies, more mandates, more taxes, more regulations.

If you're an insurer, a drug maker, a hospital, a doctor, a device maker, a pharmacist, an employer or a union boss, you don't know what the future will hold.

Maybe Congress will boost the fine on individuals and employers for not buying your product. Maybe Congress will raise or lower the special new excise tax they've levied on your industry. Maybe they'll require insurers to cover your procedure, or maybe they won't.

The one thing you know for sure: Government will never again leave you alone.

As the once and future Ways and Means Committee Chairman Charlie Rangel likes to put it, "Everything is on the table." That means you'd better pay your admission: hire Henry Waxman's legislative director as your lobbyist, contribute to Max Baucus' re-election or Charlie Rangel's legal defense fund, retain Tom Daschle as your consultant, or become a stage prop for President Obama's next "jobs bill."

Of course, health care was no free-market Wild West before now. Insurers' profits were protected by tax codes and regulations that stifled competition, drug makers' wouldn't exist without government-granted monopolies, and hospitals and doctors have been largely clients of the welfare state since Medicare and Medicaid.

But "reform" raises the stakes of health care lobbying. Lobbying Medicare to cover your procedure has long been the big fish. Now lobbying OMB to require coverage for your procedures is the whole game.

We've already seen this dynamic at work. The Senate's lobby database includes more than 1,000 lobbying reports since 2004, when the GOP created the new drug entitlement, on which "Medicare Part D" is a listed issue.

Watch whether the companies that lobbied up for last year's fight disarm or keep their standing armies. I think you'll see the likes of Bob Dole and Bill Frist -- the pro-"reform" Republicans who happened to work for health care companies -- getting a lot more work.

You'll also see the Democratic staffers who wrote the bill rewarded with plush lobbying gigs.

"Reform" spells a healthy future for K Street.

Timothy P. Carney is the Washington Examiner's Lobbying Editor. His K Street column appears on Wednesdays.