CoStar Group (CSGP) Stock Concentration Calculator
Calculator · free · no signup · CSGPQuantify CoStar Group concentration risk. Drawdown impact at 30 / 50 / 70%, with the tax-aware trade-off between selling down and hedging.
Beta · invite-only · AlphaLatitude Inc. · Free Tools
Your inputs
Adjust — results update instantly.Position & portfolio
Tax
Most fee-only advisors target ≤10% in any single name. You're at 67%.
Estimates only. Not financial advice.
Most sensitive to: Expected market return (±10% on this input swings best-plan wealth by ±$190,508).
Cost of fully de-concentrating
All three plans sell to 0% (no hedge).Sensitivity. If your expected position return drops below 19.6%/yr, lump-sum (sell everything today) beats every spread plan above.
Have multiple RSU vest lots? The RSU Lot Order Calculator picks which lots to sell first, and on which dates, to divest at the lowest computed tax.
Build your own plan
Toggle below — chart updates live. Sell buttons show the slice.Tech / Software single names hit a 50%+ peak-to-trough drawdown in roughly 1 of every 5 rolling 3-year windows over 2014–2024. Even mega-caps aren’t exempt.
Tax brackets: 2026 · Estimates only — not financial advice.
Estate note. Heirs receive a stepped-up basis at death (§1014), eliminating built-in gain on inherited shares. Older holders who plan to bequeath rather than sell may rationally never de-concentrate.
You sized one position's risk. The beta integrates hedging, sell-down, and tax timing into one optimized plan.
Request beta access →Related calculators: Protect Your Stock Calculator · RSU Lot Order Calculator · Equity Funding Plan Calculator
About CoStar Group
CoStar Group (CSGP) is a public Data company, incorporated in Delaware and headquartered in Arlington, VA.
Last close: $31.38 per share (as of 2026-08-18).
Equity grants at CoStar Group typically include restricted stock units (RSUs).
CoStar Group, Inc. is an American provider of information, analytics, and marketing services to the commercial property industry in North America and Europe. Founded in 1987 by Andrew C. Florance and based in Arlington, Virginia, the company operates the CoStar online database and news website and several online marketplaces, including Apartments.com and Homes.com.
Source: Wikipedia (CC BY-SA 4.0)
Andrew Florance founded the company in 1987 to build a commercial real estate database, and its research staff physically verifies property and lease data that is otherwise scattered and private. That proprietary collection is the moat: subscriptions to CoStar Suite are close to mandatory for brokers and appraisers. Apartments.com and, more recently, Homes.com extended the model into residential listings, funded by very large marketing campaigns. Residential expansion is the expensive bet on an established data business. Headquarters are in Arlington, Virginia.
Sources: sec.gov · en.wikipedia.org
OptionsAhoy is an independent tool and is not affiliated with, endorsed by, or sponsored by CoStar Group.
If a meaningful share of your net worth sits in CSGP, concentration risk is the question. This calculator quantifies drawdown impact at 30 / 50 / 70%, and the trade-off between selling down (tax cost now) versus hedging (option premium drag), auto-filled with CSGP's option-implied volatility.
Example: 5,000 CSGP shares at $31.38 is a $156,900 position. A 30% drawdown costs $47,070; a 50% drawdown costs $78,450; a 70% drawdown costs $109,830. The calculator quantifies the trade-off between selling down (immediate capital-gains tax) and hedging (option premium drag) using CSGP's option-implied volatility and your cost basis.
All CoStar Group tools → · Use the generic Stock Concentration Calculator for any company. Diversifying multiple RSU lots? See the lot-by-lot sell order →
CoStar Group equity questions
- How much CSGP stock is too much?
- There is no single threshold, but the larger the share of your net worth in one stock, the more a single bad year can set back your plans. The calculator above quantifies the drawdown impact at 30, 50, and 70 percent for your CSGP position and weighs selling down (which triggers capital-gains tax now) against hedging (which costs option premium).
- Does CoStar Group grant ISOs, NSOs, or RSUs?
- Equity compensation at CoStar Group typically takes the form of restricted stock units (RSUs). Restricted stock units are taxed as ordinary income when they vest.
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OptionsAhoy plans your CoStar Group equity alongside hedging, vesting, and de-concentration, across bullish, neutral, and bearish market scenarios. Free during beta.