AAMI vs NTRS: Which Is the Better Buy in 2026?

Same yardstick, side by side (as of October 2026). Valuation lined up like this is most meaningful for two names in the same corner of the market, which these are. Figures are approximate; verify before investing.

The metrics above tell you which is the marginally better business. The bigger risk for most people is not picking the slightly worse stock, it is over-concentrating. AAMI and NTRS share themes, so owning both, or adding either to what you already hold, can quietly push a large share of your portfolio into one bet.

This is the part a generic comparison page cannot answer, because it depends on what you own. Connect your brokerage and Walnut shows your real, combined AAMI and NTRS exposure, flags overlap with your existing positions, and tells you if adding one would tip you past a concentration you are comfortable with, read-only by default, with your login staying at your broker. Walnut is not an investment adviser.

Acadian Asset Management (NYSE: AAMI) is the successor to BrightSphere Investment Group, which rebranded and changed its ticker from BSIG to AAMI in early 2025 after divesting six of its seven affiliates to concentrate on a single business: Acadian, a Boston-based systematic investment manager founded in 1980. Acadian runs quantitative strategies across global equities, fixed income, and alternatives, leaning on data science, machine learning, and factor models to exploit market inefficiencies while stripping out human bias. Its client base is overwhelmingly institutional, and roughly 90% of revenue comes from equity strategies, so its fortunes track global equity markets closely.

Full AAMI guide

Northern Trust Corporation is a Chicago-based financial holding company built around two client segments: Asset Servicing (custody, fund administration, securities lending, foreign exchange and related institutional services) and Wealth Management (private banking, trust, and investment services for wealthy families, family offices, and institutions). It sits alongside BNY and State Street as one of the handful of large custody banks in the world, with roughly $18.6 trillion in assets under custody and administration and about $1.8 trillion under management as of early 2026. Most of its revenue is fee-based, which makes it more capital-light and less credit-cyclical than a traditional lending bank, though net interest income on client deposits is still a meaningful contributor.

Full NTRS guide

Both fit overlapping themes, but they are not interchangeable. The useful comparison is which set of drivers and risks you want exposure to.

• AAMI drivers: Record AUM and net flows; Operating leverage on management fees.
• NTRS drivers: Fee growth and operating leverage; Net interest income and deposits.

A faster-growing, richer-valued name usually swings harder, so it suits a longer horizon and a higher tolerance for volatility; a steadier, more cash-generative business suits a more conservative or income-minded investor. The honest test is which set of risks you could hold through a drawdown: Acadian is concentrated: over 90% of revenue comes from equity strategies, a large share of AUM sits in a handful of top strategies, and roughly 70% of AUM is denominated in non-U.S. For NTRS, as a custody bank, Northern Trust is exposed to market levels because fees scale with asset values, so an equity or bond selloff pressures revenue.

Growth-minded investors who believe the theme has years to run tend to accept the richer multiple for more upside; value-minded investors lean toward the cheaper forward earnings and steadier profile. Pick AAMI if you believe its drivers more; NTRS if you believe its. Many investors hold both, but since they share themes, that is a concentrated bet, not diversification. Decide deliberately and check overlap. For the full detail, see the AAMI and NTRS guides.

AAMI. Trailing GAAP earnings understate the run rate after a year of rapid AUM growth, which is why the trailing P/E near 33x sits far above a forward multiple near 14.5x on 2027 consensus EPS of about $6.38. That gap only closes if flows and markets cooperate, and the stock already trades near the three covering analysts' mean target of about $94, with a consensus hold rating. The small dividend means this is a growth-and-flows story, not an income name.

NTRS. At about $166.55 and a $30.5 billion market cap on October 16, 2026, Northern Trust trades near 14 times trailing and 13 times forward earnings and about 2.4 times book, a lower multiple than in mid-2026 after a pullback of about 10% over three months. Trailing earnings are flattered by an unusually strong second quarter, and analysts expect 2027 EPS near $12.71, roughly flat on 2026, so the forward multiple is the steadier reference. Figures are approximate and drawn from company reports and market data as of October 2026.

Headline figures (approximate, October 2026): AAMI shows assets under management ~$232.7B at June 30, 2026 (up ~54% year over year), revenue (ttm) ~$669M (Q2 2026 ~$183M, up ~45-47% year over year), management fees (q2 2026) ~$177M, a record, eni eps (q2 2026) ~$1.33 vs ~$1.02 consensus; NTRS shows revenue (ttm) ~$9.1B, q2 2026 revenue / net income ~$2.71B (+36% YoY) / ~$782M, eps (q2 2026 vs estimate) $4.23 vs ~$4.62, net income (ttm) ~$2.18B (net margin ~25%).

AAMI and NTRS are related but distinct: same themes, different businesses and risks. Neither wins in the abstract; the right pick is whichever thesis you actually believe, sized so you are not over-concentrated in one theme. Walnut can show your combined AAMI and NTRS exposure against your real portfolio. It is not an investment adviser.