U.S. Steel Corp., the nation's largest steel maker, said yesterday that profits plunged 46 percent for the last quarter of 1981 but more than doubled for the year compared with 1980.

U.S. Steel said fourth-quarter net income was $101.8 million ($1.13 a share) compared with $190 million ($2.16) for the 1980 period. Sales for the quarter fell to $3.3 billion from $3.4 billion.

For 1981, U.S. Steel earned $1.1 billion ($12.07) on sales of $13.9 billion compared with 1980 earnings of $504.5 million ($5.77) on sales of $12.5 billion.

Blaming a recession over which they had no control and price wars they were forced to join, Eastern Airlines and Trans World Airlines posted staggering losses yesterday for the fourth quarter of 1981 and the full year.

Eastern said it lost $29.4 million in the final quarter compared with a $6.9 million profit a year before. For the year, Eastern lost $65.9 million on top of a $17.4 million loss in 1980.

Last year's revenue was $3.73 billion, up from $3.45 billion in 1980, and fourth-quarter operating revenues totaled $892.6 million, up from the year-earlier total of $891.4 million.

TWA said it lost $46.9 million in the fourth quarter compared with a fourth-quarter 1980 loss of $29.5 million. For the year it lost $25.1 million compared with a 1980 loss of $27 million.

TWA's parent company, Trans World Corp., reported a fourth-quarter loss of $9.2 million compared with a loss of $14.7 million in 1980, but for the year it earned $64.3 million ($2.30 a share), down from $67.6 million ($2.84) in 1980.

Revenues for the year were $5.27 billion, up from 1980, while fourth-quarter revenues were $892.6 million, up from 1980.

Merrill Lynch & Co. Inc., the nation's largest investment firm, and third-ranked E.F. Hutton Group Inc. each reported yesterday that earnings rose modestly in the final three months of 1981 to set records for the period.

But both companies said reduced trading volume cut into commission revenues from extraordinary levels reached in 1980.

Merrill Lynch reported record earnings and revenues for both the fourth quarter and full year. E.F. Hutton said earnings for 1981 were down 4.6 percent from 1980's record results.

For the fourth quarter, Merrill Lynch reported earnings of $54.8 million ($1.37 a share), up from $51.7 million ($1.35) in the same 1980 period on 6 percent more outstanding shares. Revenues soared to $1.12 billion from $853 million a year earlier.

For all of 1981, earnings rose to $202.9 million from $201.1 million in 1980, while revenues jumped 34 percent to $4.04 billion from $3.02 billion. Earnings per share fell to $5.14 from $5.45 in 1980 as the number of outstanding shares rose an average 9 percent over the year.

E.F. Hutton said fourth-quarter profits rose to $23.6 million from $23.3 million in the same 1980 period. Commission revenues declined by 29 percent from the final quarter of 1980.

Earnings per share fell to $1.27 from $1.33, reflecting the issuance of $60 million of convertible debentures in November 1980.

Revenues rose 29 1/2 percent to $405 million from $313 million in the final three months of 1980.

For the full year, earnings fell to $78.8 million from $82.6 million in 1980, and revenues rose 28.4 percent to $1.444 billion from 1.125 billion.

Earnings per share fell to $4.31 from $4.93 in 1980.

Union Pacific Corp., a railroad operator and energy producer, said yesterday that fourth-quarter earnings rose nearly 21 percent, despite the recession, a squeeze on oil-refining profits, and declining rail traffic.

Earnings for the final quarter of 1981 were $126 million ($1.31 a share), up from $105.2 million ($1.09) in the final quarter of 1980. Revenue rose to $1.6 billion from $1.33 billion.

For the full year, profits were $410.7 million ($4.27), Exxon, Socal, Amoco Report Declines in 4th-Quarter Profits U. S. Steel Lower ---6-------------------------------------------------- From News Services

U.S. Steel Corp., the nation's largest steel maker, said yesterday that profits plunged 46 percent for the last quarter of 1981 but more than doubled for the year compared with 1980.

U.S. Steel said fourth-quarter net income was $101.8 million ($1.13 a share) compared with $190 million ($2.16) for the 1980 period. Sales for the quarter fell to $3.3 billion from $3.4 billion.

For 1981, U.S. Steel earned $1.1 billion ($12.07) on sales of $13.9 billion compared with 1980 earnings of $504.5 million ($5.77) on sales of $12.5 billion.

Blaming a recession over which they had no control and price wars they were forced to join, Eastern Airlines and Trans World Airlines posted staggering losses yesterday for the fourth quarter of 1981 and the full year.

Eastern said it lost $29.4 million in the final quarter compared with a $6.9 million profit a year before. For the year, Eastern lost $65.9 million on top of a $17.4 million loss in 1980.

Last year's revenue was $3.73 billion, up from $3.45 billion in 1980, and fourth-quarter operating revenues totaled $892.6 million, up from the year-earlier total of $891.4 million.

TWA said it lost $46.9 million in the fourth quarter compared with a fourth-quarter 1980 loss of $29.5 million. For the year it lost $25.1 million compared with a 1980 loss of $27 million.

TWA's parent company, Trans World Corp., reported a fourth-quarter loss of $9.2 million compared with a loss of $14.7 million in 1980, but for the year it earned $64.3 million ($2.30 a share), down from $67.6 million ($2.84) in 1980.

Revenues for the year were $5.27 billion, up from 1980, while fourth-quarter revenues were $892.6 million, up from 1980.

Merrill Lynch & Co. Inc., the nation's largest investment firm, and third-ranked E.F. Hutton Group Inc. each reported yesterday that earnings rose modestly in the final three months of 1981 to set records for the period.

But both companies said reduced trading volume cut into commission revenues from extraordinary levels reached in 1980.

Merrill Lynch reported record earnings and revenues for both the fourth quarter and full year. E.F. Hutton said earnings for 1981 were down 4.6 percent from 1980's record results.

For the fourth quarter, Merrill Lynch reported earnings of $54.8 million ($1.37 a share), up from $51.7 million ($1.35) in the same 1980 period on 6 percent more outstanding shares. Revenues soared to $1.12 billion from $853 million a year earlier.

For all of 1981, earnings rose to $202.9 million from $201.1 million in 1980, while revenues jumped 34 percent to $4.04 billion from $3.02 billion. Earnings per share fell to $5.14 from $5.45 in 1980 as the number of outstanding shares rose an average 9 percent over the year.

E.F. Hutton said fourth-quarter profits rose to $23.6 million from $23.3 million in the same 1980 period. Commission revenues declined by 29 percent from the final quarter of 1980.

Earnings per share fell to $1.27 from $1.33, reflecting the issuance of $60 million of convertible debentures in November 1980.

Revenues rose 29 1/2 percent to $405 million from $313 million in the final three months of 1980.

For the full year, earnings fell to $78.8 million from $82.6 million in 1980, and revenues rose 28.4 percent to $1.444 billion from 1.125 billion.

Earnings per share fell to $4.31 from $4.93 in 1980.

Union Pacific Corp., a railroad operator and energy producer, said yesterday that fourth-quarter earnings rose nearly 21 percent, despite the recession, a squeeze on oil-refining profits, and declining rail traffic.

Earnings for the final quarter of 1981 were $126 million ($1.31 a share), up from $105.2 million ($1.09) in the final quarter of 1980. Revenue rose to $1.6 billion from $1.33 billion.

For the full year, profits were $410.7 million ($4.27), up from $404.5 million ($4.22). Revenue grew to $6.38 billion from $4.87 billion.