Even as other companies and trade groups intensified their focus on Capitol Hill, beleaguered BP reported sharply reduced lobbying spending for the first half of this year, according to recent Congressional disclosure forms.

BP, whose exploded rig in the Gulf of Mexico caused a multi-month spill, reported spending $3.3 million to lobby in the first half of this year, about 43 percent of what it shelled out in the first six months of 2009. Although it has been a high-profile figure in the influence industry over the past few months, its spending did not put it on Roll Call’s list of the top 20 biggest spenders. Indeed, BP wouldn’t even make it into the top 50.

The new filings show that BP spent $1.7 million in this year’s second quarter, which included the April 20 spill. By comparison, the company spent $4 million in the second quarter of last year. Between the first and second quarters of this year, BP increased spending by $120,000.

The lobbying filings, which were due at the end of the day Tuesday, also show sustained or increased activity by other companies with high stakes in Congressional or executive branch action, such as financial reform, climate change legislation, labor regulations and telecommunications mergers. The 20 biggest spenders for the first half of this year included aviation giant Boeing Co., big business lobby U.S. Chamber of Commerce and senior citizens group AARP.

While responding to the oil spill has consumed the nation’s capital since the environmental catastrophe occurred, BP’s five-page lobbying report filed Tuesday evening includes only one reference to “the Gulf of Mexico incident.”

The lobbying filings, however, do not reflect all of the resources the company has expended on Capitol Hill. That’s because preparation for Congressional testimony is not considered a reportable lobbying expense.

BP’s Washington, D.C., office also filed late Tuesday an amendment to its first-quarter report revising its spending for those three months to $1.6 million from $3.5 million. The amended filing shows the substantially lower figure, but the originally filed and amended forms appear to be almost identical, including the same number of lobbyists employed and issues covered.

BP spokesman Scott Dean said the downward revision was attributable to a change in the reportable dues the company paid to the American Petroleum Institute, Big Oil’s lobbying organization. He said that prior to this year, API used a more expansive IRS definition of lobbying that included grass-roots and state-level lobbying. The switch to the more narrow lobbying definition, Dean said, “has resulted in a substantial reduction of BP’s reportable lobbying expenditures.”

Craig Holman, a lobbyist for the liberal group Public Citizen, said that from a public relations standpoint, it benefits BP to report less lobbying activity.

“It looks bad for BP to have a high dollar figure attached to lobbying Congress while they are in the middle of this disaster,” he said.

The change in API’s lobbying definition did not appear to have a uniform effect on spending trends among the organization’s members. Other energy companies reported higher lobbying expenditures this year, including ConocoPhillips, which spent more than $11.9 million for the first half of 2010, a $2.7 million increase, and Shell, which spent more than $6.2 million since January, an increase of more than $1.1 million.

Anadarko Petroleum Corp., a minority partner in BP’s ill-fated Gulf operation, reported spending $2.5 million in the first half of this year, an increase of $1.6 million or 188 percent from the same period in 2009. On the other hand, oil giant Exxon Mobil Corp. reported spending nearly $7.7 million less during the first half of 2010 than that period in 2009.

API, which like BP is not among the top 20 biggest spenders, reported almost $3.6 million for the first half of the year, $100,000 less than in the first half of 2009.

Even as it reported less in-house lobbying, BP’s filings did show an increase in payments to outside lobbying firms in the second quarter to $430,000 from $300,000 in the first three months of the year. The company paid a total of seven outside firms in each quarter.

In the second quarter, BP doubled its payments to the Podesta Group and the Alpine Group to $120,000 from $60,000 in the first quarter. It also paid the Duberstein Group $100,000 in both the first and second quarters.

Outside the energy sector, other companies were also engaged in major lobbying fights.

FedEx Corp., which has waged a high-dollar campaign to fight legislation supported by UPS that would allow FedEx drivers to join unions, spent $7 million on lobbying in the second quarter, compared with $4.9 million in the first quarter.

Comcast Corp., which is seeking federal approval to buy NBC Universal, spent $3.9 million in the second quarter, up from $3 million in the first three months.

And the American Medical Association, which has been lobbying Congress to prevent cuts in Medicare payments to doctors, spent $8.6 million in the second quarter, compared with $6.2 million in the first period.