The four sentences (labelled 1, 2, 3, 4) below, when properly sequenced would yield a coherent paragraph. Decide on the proper sequencing of the order of the sentences and key in the sequence of the four numbers as your answer:

1. It advocated a conservative approach to antitrust enforcement that espouses faith in efficient markets and voiced suspicion regarding the merits of judicial intervention to correct anticompetitive practices.

2. Many industries have consistently gained market share, the lion’s share – without any official concern; the most successful technology companies have grown into veritable titans, on the premise that they advance ‘public interest’.

3. That the new anticompetitive risks posed by tech giants like Google, Facebook, and Amazon, necessitate new legal solutions could be attributed to the dearth of enforcement actions against monopolies and the few cases challenging mergers in the USA.

4. The criterion of ‘consumer welfare standard’ and the principle that antitrust law should serve consumer interests and that it should protect competition rather than individual competitors was an antitrust law introduced by, and named after, the 'Chicago school'.

The correct sequencing for the sentences to form a coherent paragraph is 4123.

Here is the step-by-step logical breakdown of the sequencing:

Step 1: Identifying the opening sentence and establishing a mandatory link (4 and 1)
Sentence 4 introduces a specific concept: the "consumer welfare standard" and the principle of antitrust law introduced by the 'Chicago school'. Sentence 1 begins with the pronoun "It" ("It advocated a conservative approach..."). The pronoun "It" refers back to the 'Chicago school' mentioned in sentence 4. Therefore, sentence 4 must immediately precede sentence 1, establishing the link 4-1.

Step 2: Linking the policy to the real-world outcome (1 and 2)
Sentence 1 explains that this school of thought advocated for a conservative approach to antitrust enforcement with little judicial intervention. Sentence 2 describes the direct consequence of this hands-off approach: industries gaining market share "without any official concern" and technology companies growing into massive titans on the assumption that they serve the public interest. This connects the theory in 4-1 to the state of affairs described in 2.

Step 3: Connecting the general trend to specific examples and solutions (2 and 3)
Sentence 2 mentions successful technology companies growing into veritable titans. Sentence 3 specifies these tech giants by name ("Google, Facebook, and Amazon") and argues that the new anticompetitive risks they pose necessitate new legal solutions. It attributes this need to the historical lack of enforcement actions and merger challenges, which stems directly from the conservative policy introduced in 4-1 and observed in 2. Thus, sentence 3 logically follows sentence 2.

Conclusion:
Combining these connections, we get the coherent flow: 4 -> 1 -> 2 -> 3 (Sequence: 4123).