William Beaver House (15 William Street)
1. BUILDING OVERVIEW (ANALYST FRAMING)
15 William Street (William Beaver House) is a mature resale condo completed in 2008, consisting of 186 units across 47 floors. Based on post-sponsor behavior, the building is classified as Yield-Oriented. While it outperforms the Financial District sub-market baseline by 9.4% in absolute pricing, it functions primarily as a high-velocity rental asset where capital appreciation is stalled. Resale data indicates a building that is mean-reverting toward its original 2008–2010 sponsor baselines, significantly underperforming the NYXRCSA index, which has grown to 331.14 as of late 2025.
2. UNIT MIX & COMPOSITION
Based on transaction-weighted data, the building is heavily weighted toward small-to-mid-size footprints, which drives its high rental churn.
1BR: 263 sales (approx. 54% of activity). Median PPSF: $1,350.
2BR: 151 sales (approx. 31% of activity). Median PPSF: $1,343.
Studios: 43 sales (approx. 8.8% of activity). Median PPSF: $1,339.
3BR+: 7 sales (approx. 1.4% of activity). Median PPSF: $1,604.
Analysis: The 54% concentration of 1BR units provides high liquidity for the rental market but creates a unit mix imbalance during resale cycles, as these units face significant competition from a high-velocity secondary market.
3. LINE (STACK) PERFORMANCE — RESALE ONLY
Liquidity (Fastest Lines): The Line E (2BR) and Line H (2BR) stacks exhibit the highest relative resale velocity. Recently, Unit 29E cleared in 19 days, while Unit 22H cleared in 24 days.
Price Strength: Line B and Line C (1BRs) command consistent PPSF premiums ($1,350–$1,400+), while Line A and Line H (2BRs) often trade at a discount relative to the building median, frequently dipping to $1,000–$1,200 PPSF.
Appreciation: Post-sponsor compounding is negligible. For example, Line B (1BR) units that traded at ~$1,200 PPSF in 2008 are reselling for ~$1,219 PPSF in 2024, representing a CAGR of ~0.1%. This is nearly zero real growth compared to the NYXRCSA index.
4. BUILDING-WIDE PPSF TREND (NORMALIZED)
2008–2014: Sponsor Establishment Phase. Pricing was established between $1,100 and $1,400 PPSF.
2015–2021: Flat/Cyclical. Resale pricing remained largely trapped within the $1,200–$1,400 range with occasional outliers.
2022–2025: Mean-Reverting. Recent 2025 sales like Unit 7H ($1,063 PPSF) and Unit 22H ($1,161 PPSF) show pricing returning to 2008–2009 levels.
Conclusion: Flat. The building has failed to capture any sustained capital compounding over its 17-year history.
5. RENT CAPTURE ANALYSIS
Mandatory Metric: Effective Annual Rent (EAR)
Unit 37F (1BR, 2025): Achieved $5,500. DOM: 13. EAR: $5,304.
Unit 31G (1BR, 2025): Achieved $5,000. DOM: 135. EAR: $3,150.
Unit 39E (2BR, 2025): Achieved $8,500. DOM: 163. EAR: $4,704.
Analysis: The building experiences massive income leakage. While nominal rents are strong ($70–$80 PPSF), units with absorption friction (DOM > 100) lose 37% to 45% of their annual income to vacancy.
6. B³ SCORING SYSTEM (0–100)
Liquidity Score: 58 (High historical volume but significant resale friction; building median DOM of 112 days indicates exit resistance).
Rent Capture Score: 62 (Strong nominal rent per SF, but consistent leakage due to high absorption times in mid-tier units).
Appreciation Score: 42 (Weak CAGR; most lines are mean-reverting to 15-year-old pricing, severely trailing the NYXRCSA index).
7. COMPOSITE SCORE & CLASSIFICATION
Composite Score: 53.6
Category: Yield-Oriented
Justification: The building functions as a high-output rental factory (372 rentals) but fails as a capital preservation vehicle due to flat-to-negative compounding.
8. TRANSACTION EXAMPLES
Resale Appreciation (Nominal)
Unit 29E (2BR): $1,480,000 (2014) → $1,760,000 (2025). +18.9% (+1.6% CAGR). Driver: Market regime timing.
Unit 25E (2BR): $1,675,000 (2020) → $1,815,000 (2023). +8.3% (+2.7% CAGR). Driver: Market regime timing.
Resale Depreciation/Stagnation
Unit 21B (1BR): $1,069,162 (2008) → $965,000 (2024). -9.7%. Driver: Unit size / unit mix imbalance.
Unit 14B (1BR): $1,142,985 (2009) → $1,028,000 (2022). -10%. Driver: Sponsor price normalization.
Unit 24H (2BR): $1,595,000 (2019) → $1,424,600 (2022). -10.7%. Driver: Liquidity shift (DOM change).
Unit 30E (2BR): $1,890,000 (2009) → $1,620,000 (2024). -14.2%. Driver: Liquidity shift (DOM change).
9. RISKS & RED FLAGS
Extreme Income Leakage: Rental DOM for 1BR/2BR units frequently exceeds 130 days (e.g., Units 31G and 39E), which destroys annual yield.
Capital Stagnation: The building's median PPSF in 2025 ($1,352) is virtually identical to trades seen in 2014–2015 ($1,350+), indicating zero growth over a decade.
Red Flag: Do not buy Line B or Line H for capital growth; they show the most consistent price erosion and high absorption friction.
10. EXECUTIVE SUMMARY
15 William Street is a Yield-Oriented asset that serves as a high-velocity rental factory in the Financial District but fails to deliver capital compounding. Post-sponsor behavior is characterized by flat-to-negative price persistence, with most units reselling at or below their inflation-adjusted 2008–2010 baselines. While nominal rents appear attractive, investors suffer from significant income leakage due to absorption times (DOM) often exceeding four months. The building’s 9.4% outperformance of its sub-neighborhood is an absolute price leader, but a relative performance laggard in terms of compounding.
B³ SCORECARD
Liquidity Score: 58
Rent Capture Score: 62
Appreciation Score: 42
Composite Score: 53.6
Category: Yield-Oriented
Unit Mix: 1BR Dominant (54%)
Disclosures: Approximately 185 transactions from 2008–2014 were reclassified as Sponsor-Driven due to the <30 day DOM rule or "No Listing" status. This normalization reveals that the true resale median DOM of 112 days is 18% higher than the building's aggregate reported average, and true resale appreciation has been near-zero for over a decade.