WST vs. SPY

Last updated Jun 3, 2026

WST (West Pharmaceutical Services, Inc.) is a stock, while SPY (State Street SPDR S&P 500 ETF) is S&P 500 fund tracking the S&P 500 Index. Over the past 10 years, WST returned 15.72%/yr vs 15.57%/yr for SPY. At a 0.44 correlation, their price movements are largely independent.

Performance

WST vs. SPY - Performance Comparison

The chart below illustrates the hypothetical performance of a $10,000 investment in West Pharmaceutical Services, Inc. (WST) and State Street SPDR S&P 500 ETF (SPY). The values are adjusted to include any dividend payments, if applicable.

Returns By Period

In the year-to-date period, WST achieves a 13.65% return, which is significantly higher than SPY's 11.69% return. Both investments have delivered pretty close results over the past 10 years, with WST having a 15.72% annualized return and SPY not far behind at 15.57%.

WST

• 1D: -1.31%
• 1M: 3.82%
• YTD: 13.65%
• 6M: 14.53%
• 1Y: 49.58%
• 3Y*: -2.89%
• 5Y*: -1.01%
• 10Y*: 15.72%

SPY

• 1D: 0.14%
• 1M: 5.40%
• YTD: 11.69%
• 6M: 12.09%
• 1Y: 29.62%
• 3Y*: 22.64%
• 5Y*: 14.20%
• 10Y*: 15.57%

*Multi-year figures are annualized to reflect compound growth (CAGR)

WST vs. SPY - Yearly Performance Comparison

	2026 (YTD)	2025	2024	2023	2022	2021	2020	2019	2018	2017
WST West Pharmaceutical Services, Inc.	13.65%	-15.73%	-6.75%	49.97%	-49.70%	65.88%	89.05%	54.13%	-0.08%	17.02%
SPY State Street SPDR S&P 500 ETF	11.69%	17.72%	24.89%	26.18%	-18.18%	28.73%	18.33%	31.22%	-4.57%	21.71%

Correlation

The correlation between WST and SPY is 0.33, which is low. Their price movements are largely independent, making them effective diversification partners.

	Correlation
Correlation (1Y) Calculated over the trailing 1-year period	0.33
Correlation (3Y) Calculated over the trailing 3-year period	0.37
Correlation (5Y) Calculated over the trailing 5-year period	0.48
Correlation (10Y) Calculated over the trailing 10-year period	0.49
Correlation (All Time) Calculated using the full available price history since Feb 1, 1993	0.44

The correlation between WST and SPY shifts across timeframes, from 0.33 (1 year) to 0.49 (10 years), reflecting how their relationship changes across market environments.

Return for Risk

WST vs. SPY — Risk / Return Rank

Compare risk-adjusted metric ranks to identify better-performing investments over the past 12 months.

WST

WST Risk / Return Rank: 75
WST Sharpe Ratio Rank: 76
WST Sortino Ratio Rank: 79
WST Omega Ratio Rank: 75
WST Calmar Ratio Rank: 74
WST Martin Ratio Rank: 71

SPY

SPY Risk / Return Rank: 75
SPY Sharpe Ratio Rank: 77
SPY Sortino Ratio Rank: 75
SPY Omega Ratio Rank: 76
SPY Calmar Ratio Rank: 68
SPY Martin Ratio Rank: 80

The rank (0–100) shows how this investment's returns compare to the risk taken. Higher = better. Based on the past 12 months of data, combining Sharpe, Sortino, and other metrics used by quantitative funds and institutional investors.

WST vs. SPY - Risk-Adjusted Trends Comparison

This table presents a comparison of risk-adjusted performance metrics for West Pharmaceutical Services, Inc. (WST) and State Street SPDR S&P 500 ETF (SPY). Risk-adjusted metrics are performance indicators that assess an investment's returns in relation to its risk, enabling a more accurate comparison of different investment options.

	WST	SPY	Difference
Sharpe ratio Return per unit of total volatility	1.21	2.52	-1.31
Sortino ratio Return per unit of downside risk	2.25	3.42	-1.16
Omega ratio Gain probability vs. loss probability	1.27	1.46	-0.19
Calmar ratio Return relative to maximum drawdown	1.96	3.42	-1.45
Martin ratio Return relative to average drawdown	3.94	15.93	-11.99
Data is calculated on a 1-year rolling basis and updated daily. The trend shows the change in the indicator over the past month.

WST vs. SPY - Sharpe Ratio Comparison

The current WST Sharpe Ratio is 1.21, which is lower than the SPY Sharpe Ratio of 2.52. The chart below compares the historical Sharpe Ratios of WST and SPY, calculated using daily returns over the previous 12 months. A higher Sharpe Ratio indicates better risk-adjusted performance relative to the risk-free rate.

Sharpe Ratios by Period

	WST	SPY	Difference
Sharpe Ratio (1Y) Calculated over the trailing 1-year period	1.21	2.52	-1.31
Sharpe Ratio (5Y) Calculated over the trailing 5-year period	-0.03	0.84	-0.86
Sharpe Ratio (10Y) Calculated over the trailing 10-year period	0.46	0.87	-0.42
Sharpe Ratio (All Time) Calculated using the full available price history	0.39	0.59	-0.20

Drawdowns

WST vs. SPY - Drawdown Comparison

The maximum WST drawdown since its inception was -59.29%, which is greater than SPY's maximum drawdown of -55.19%. Use the drawdown chart below to compare losses from any high point for WST and SPY.

Drawdown Indicators

	WST	SPY	Difference
Max Drawdown Largest peak-to-trough decline	-59.29%	-55.19%	-4.10%
Max Drawdown (1Y) Largest decline over 1 year	-24.70%	-8.88%	-15.82%
Max Drawdown (3Y) Largest decline over 3 years	-53.79%	-18.76%	-35.03%
Max Drawdown (5Y) Largest decline over 5 years	-59.29%	-24.50%	-34.79%
Max Drawdown (10Y) Largest decline over 10 years	-59.29%	-33.72%	-25.57%
Current Drawdown Current decline from peak	-32.97%	0.00%	-32.97%
Average Drawdown Average peak-to-trough decline	-16.88%	-9.05%	-7.83%
Ulcer Index Depth and duration of drawdowns from previous peaks	12.32%	1.91%	+10.41%

Volatility

WST vs. SPY - Volatility Comparison

West Pharmaceutical Services, Inc. (WST) has a higher volatility of 8.65% compared to State Street SPDR S&P 500 ETF (SPY) at 2.75%. This indicates that WST's price experiences larger fluctuations and is considered to be riskier than SPY based on this measure. The chart below showcases a comparison of their rolling one-month volatility.

Volatility by Period

	WST	SPY	Difference
Volatility (1M) Calculated over the trailing 1-month period	8.65%	2.75%	+5.90%
Volatility (6M) Calculated over the trailing 6-month period	25.52%	8.89%	+16.63%
Volatility (1Y) Calculated over the trailing 1-year period	41.28%	11.81%	+29.47%
Volatility (5Y) Calculated over the trailing 5-year period, annualized	40.56%	17.05%	+23.51%
Volatility (10Y) Calculated over the trailing 10-year period, annualized	34.63%	17.94%	+16.69%

Dividends

WST vs. SPY - Dividend Comparison

WST's dividend yield for the trailing twelve months is around 0.28%, less than SPY's 0.97% yield.

Position	TTM	2025	2024	2023	2022	2021	2020	2019	2018	2017	2016	2015
SPY State Street SPDR S&P 500 ETF	0.97%	1.07%	1.21%	1.40%	1.65%	1.20%	1.52%	1.75%	2.04%	1.80%	2.03%	2.06%
WST West Pharmaceutical Services, Inc.	0.28%	0.31%	0.25%	0.22%	0.31%	0.15%	0.23%	0.41%	0.58%	0.54%	0.58%	0.75%

Frequently Asked Questions

Can I hold both WST and SPY in my portfolio?

WST and SPY have a correlation of 0.33, meaning they provide meaningful diversification benefit when combined. Depending on your allocation goals, holding both could reduce overall portfolio risk.

Which is riskier, WST or SPY?

WST has higher volatility (8.65%) compared to SPY (2.75%). In terms of maximum drawdown, WST dropped -59.29% vs SPY's -55.19%.

Which has better risk-adjusted returns?

SPY currently has the higher Sharpe Ratio (2.52 vs 1.21), meaning it's delivered slightly more return per unit of risk over the trailing 12 months. However, this ranking shifts over time - use the Risk/Return Score above for a more comprehensive view that combines Sharpe, Sortino, and other measures used by quantitative funds.