delivered the opinion of ,the Court.

Petitioner, a resident of New York, was a member of the New York Stock Exchange. He was engaged in the business of trading in securities on the floor of the Exchange for the partnership of Hilson & Neuberger, of which he was a member, executing orders on behalf of customers of the partnership. In addition he made numerous purchases and sales of securities for his own account.

During the year 1932, the one here in question, Hilson & Neuberger derived a profit of $142,802.29 from the sale of securities which were not capital assets as defined in § 101 of the Revenue Act of 1932. 47 Stat. 169,191. The firm had other income of $170,830.65 and deductions- of $203,981.78, or net income of $109,651.16. Petitioner’s distributive share was $44,158.55. During the same year petitioner sustained a net loss of $25,588.93 on his private transactions in stocks and bonds which were not capital assets as defined in § 101.

In his income tax return for the year 1932 petitioner deducted from gross income the loss of $25,588.93. The Commissioner disallowed the deduction arid assessed a deficiency. The Board of Tax Appeals upheld the action of the Commissioner. 37 B. T. A. 223. On appeal the[*85] Second Circuit Court of Appeals affirmed. 104 F. 2d 649. Because of substantial conflict with Jennings v. Commissioner, 110 F. 2d 945, and Craik v. United States, 31 F. Supp. 132, we granted certiorari limited to the questions whether § 23 (r) (1) of the Revenue Act of 1932, 47 Stat. 169, 183, authorized the- claimed deduction, and whether, in the event that it did not, the statute as so construed was constitutional. 310 U. S. 655.

Section 23 of the Revenue Act of 1932 sets out the aUowablé deductions from gross income. Section 23 (r) (1) provides:

“Losses from sales or exchanges of stocks and bonds (as defined in subsection (t) of this section) which are not capital assets (as defined in section 101) shall be allowed [as deductions from gross income] only to the extent of the gains from such sales or exchanges . . .”

The basic and narrow question is whether, in computing the income of an individual partner, the word “gains” in § 23 (r) (1) includes gains from sales or exchanges of partnership stocks and bonds which are not capital assets as defined in § 101. We are of opinion that it does.

In computing gross income prior to the Revenue Act of 1932, subject to certain limitations a taxpayer was. entitled to deduct the full amount of his losses from transactions in securities. Revenue Act of 1928, §§23 (e), 23 (g), 101 (b), 113. But the growing custom of diminishing ordinary income by deducting losses realized on the sale of securities which had shrunk in value, due no doubt to the fall in prices after 1929, led Congress to provide in § 23 (r) (1) that deductions for such losses should be limited to gains from similar, transactions.

That this was the purpose and the only purpose of § 23 (r) (1) abundantly appears from the Report of the Senate Finance Committee accompanying the bill. ^[1] Nowhere[*86] does there appear any intention to deny to a taxpayer who chooses to execute part of his security transactions in partnership with another the right to deductions which plainly would be available to him if he had executed all of them singly. Nowhere is there any suggestion that Congress intended to tax noncapital security gains until they exceeded similar losses. The language of § 23 (r) (1) does not require such a construction. Nor do the available evidences of Congressional intent indicate such a purpose.

Respondent points out, however, that under §§ 181-189 of the Revenue Act of 1932, 47 Stat. 169, 222-223, ^[2] part[*87] nership income is computed on an entity basis, that items of partnership gross income do not appear on a partner’s return, that only partnership net income is reflected in the individual partner’s income and is reported only in the form of a distributable or distributed share. He contends that since partnership income is computed in the same way as an individual’s the deduction afforded by § 23 (r) (1) to the partnership is a distinct privilege not to be confused or combined with that afforded to the individual. Thus, he argues, the deduction claimed here is inconsistent with the general scheme created for reporting partnership income as well as, in effect, a second or double use of § 23 (r) (1).

[*88] It is not to be doubted that in the enactment of § 23 (r) (1) Congress intended not only to deal with individual security gains and losses, but also, to permit losses suffered in partnership security transactions to be applied against partnership gains in like transactions. It does, not follow, however, and the language of the statute does not provide, either expressly or by necessary implication, that losses sustained in an individual capacity may not be set off against gains from identical though distinct partnership dealings. If the individual losses are actually incurred in .^similar transactions it cannot justly be said that the same deduction is taken a second time, or that the real purpose of the statute, which is ultimately to tax the net income of the individual partner, would thereby be impaired.

Sections 181-189 of the. Revenue Act of 1932, 47 Stat. 169, 222-223, provide generally for computation and reporting of partnership income. In requiring a partnership informational return . although only individual partners pay any tax, Congress recognized the partnership both as a business unit and as an association of individuals. This weakens rather than strengthens respondent’s argument that the privileges are distinct or that the unit characteristics of the partnership must be emphasized. Compare Jennings v. Commissioner, 110 F. 2d 945; Craik v. United States, 31 F. Supp. 132; United States v. Coulby, 251 F. 982 (affirmed, 258 F. 27). Nor is the deduction, claimed here precluded because Congress, in §§ 184-188, has particularized instances where partner-, ship income retains its identity in the individual partner’s return. The - maxim expressio unius est exchmo cd-terius is an aid to construction, not a rule of law. It can never override clear and contrary evidences of Congressional intent. United States v. Barnes, 222 U. S. 513.

It is true that the Treasury Department adopted a contrary position and denied the claimed deduction. G.[*89] C. M. 14012, XIY-1 Cum. Bull. 145; I. T. 2892, XIV-1 Cum. Bull. 148. Under different circumstances great weight has been attached to administrative practice and Treasury rulings, but beyond question they cannot narrow the scope of a statute when Congress plainly has intended otherwise. Rasquin v. Humphreys, 308 U. S. 54; Norwegian Nitrogen Products Co. v. United States, 288 U. S. 294.

It is true, too, that in some cases the characteristics of partnerships as business units have been emphasized, Forres v. Commissioner, 25 B. T. A. 154; Wilson v. Commissioner, 17 B. T. A. 976 (appeal dismissed, 55 F. 2d 1086); Burns v. Commissioner, 12 B. T. A. 1209; Appeal of Menken, 8 B. T. A. 1062, while in others the characteristics of partnerships as associations of individuals have been stressed. United States v. Coulby, supra. Compare Bence v. United States, 18 F. Supp. 848. These cases, not decided under' the Revenue Act of 1932, and turning, as they must, on: their own peculiar facts, are little aid in ascertaining the effect to be given to § 23 (r) (1).

It is not true, however, as respondent argues, that the asserted deduction cannot be allowed because petitioner has suggested no way to calculate it properly or to import items of gross income from the partnership informational return. The Board of Tax Appeals expressly found the amount of partnership gains from security transactions and the proportion in which petitioner was to share in the profits of the partnership. 37 B. T. A. 223, 224. Since petitioner’s share of these noncapital security gains is greater than his loss of $25,588.93, the limit on deductions set by § 23 (r) (1) is not exceeded.

Our conclusion that this is the proper construction of § 23 (r) (1) is confirmed by the action of Congress since 1932. In 1933 Congress amended § 182 (a) of the Revenue Act of 1932 to deny to individual partners deductions for partnership losses which had.been disallowed in the[*90] partnership return, the converse of the instant case. 48 Stat. 195, 209. ^[3] More significantly, in 1938, after the Treasury Department had ruled to the contrary, G. C. M. 14012, XIY-1 Cum. Bull. 145; I. T. 2892, XIV-1 Cum. Bull. 148, Congress expressly provided for the deduction of individual security losses from similar partnership gains. Revenue Act, of 1938, §§ 182-183 ; 52 Stat. 447, 521. ^[4] That the amendment , of 1933 changed and the Revenue Act of 1938 restored the law of 1932 as we have explained it is plain from the legislative history of the two Acts and of § 23 (r) (1).

Shearer v. Burnet, 285 U. S. 228, is not contrary to the conclusión we reach here. There the decision turned on the proper construction to be given to § 218 (a) of the Revenue Act of 1924, 43 Stat. 253, 275, and the court correctly concluded that Congress had not intended to allow the asserted credit.

We conclude that petitioner is entitled to the deduction. The decision of the Second Circuit Court of Appeals is reversed, and the case is remanded with directions[*91] to remand to the Board of Tax Appeals for proceedings in conformity with this opinion.

Reversed.