<p>The OP's question was about merit aid, not need-based aid. </p>
<p>I think Chicago has been generous with merit aid because it's had to be to get the top students it wants. Its reputation in the academic world is stellar, but it doesn't have the same kind of instant name recognition among the public generally that the Ivies, Stanford, MIT and a few others have. A lot of people still hear the name and assume it's either public (like, say, the University of Cincinnati) or a Catholic school (like, say, the University of San Francisco or Saint Louis University). Savvy college applicants know it's a top-tier private institution, but for a variety of reasons it doesn't end up at the top of many people's wish list. </p>
<p>As a wise old professor of mine used to the, "The terms of trade don't favor the Midwest." East Coast kids generally prefer to stay on the East Coast, or possibly head to California. West Coast kids generally prefer to stay on the West Coast, or go to the East Coast. Midwest kids either stay in the Midwest---in which case, most have some pretty darned good in-state public options like Michigan, Wisconsin, or UIUC---or, if they prefer to go private, are as likely to head for the East or West Coasts as they are to stay in the Midwest. (That's why some really terrific Midwest LACs like Carleton, Grinnell, Macalester, and Oberlin also have significantly higher acceptance rates and lower yields than their coastal counterparts; and why, in some cases, they also offer merit aid). </p>
<p>Also, the University of Chicago has earned (and in some ways cultivated) a reputation over the years as a nerdy, grinding, extremely hard-working, deeply intellectual place where the usual sorts of college fun and frivolity are hard to come by. That appeals to some, but a tender few.</p>
<p>But I do think in recent years the University of Chicago has been one of the chief beneficiaries of the US News rankings, and the obsession with "prestige" that it's engendered. Very few applicants are going to get into HYPSM and the other Ivies. A lot of very well qualified applicants are determined to go to the "most prestigious" school they can get into. So schools like Chicago, Duke, Northwestern, WUSTL, JHU, Emory, and Rice are lurking around, always toward the top of the US News rankings, ready to sweep up this year's crop of HYPSM and Ivy rejects. As a consequence, Chicago's acceptance rate is falling dramatically, and its yield is rising. I'd expect that to continue. If it does, merit aid may become less important to the school in the years to come.</p>