Dollar cost averaging (DCA) in PRTA means investing a fixed amount at regular intervals, regardless of share price. This strategy reduces timing risk and builds wealth steadily through market ups and downs.
How This Calculator Works
Our DCA calculator simulates real market conditions using historical price data. It accounts for dividend reinvestment (DRIP), where each dividend payment automatically purchases additional shares. You can adjust the investment amount, frequency, time period, and compare against benchmarks like the S&P 500 and Nasdaq-100.
Same amount invested each month — only the day of purchase changes. How much does intra-month timing actually matter?
Best Timing DCA
StrategyBuy on monthly low
Total Return-27.9%
Final Value$34.6K
Perfectly timed — impossible in practice
Your DCA
StrategyBuy on 1st of month
Total Return-34.3%
Final Value$31.5K
Consistent — no timing needed
Worst Timing DCA
StrategyBuy on monthly high
Total Return-39.9%
Final Value$28.8K
Worst possible — still beats not investing
Best vs Worst gap12.0 pp
Your timing vs best-6.4%
Your timing vs worst+5.6%
If You Keep Investing…
Based on this stock's historical CAGR of -6.4%/yr — put in vs. walk away with.
Your Plan
At $500/mo, this could grow into:
3 Years$18K~1.0x your moneyfrom $18K invested
5 Years$30K~1.0x your moneyfrom $30K invested
10 Years$60K~1.0x your moneyfrom $60K invested
20 Years$120K~1.0x your moneyfrom $120K invested
Compare Other Monthly Amounts
Same CAGR assumption. Use this to pressure-test different monthly commitments.
Monthly
3 Years~1.0x your money
5 Years~1.0x your money
10 Years~1.0x your money
20 Years~1.0x your money
$100/mo
$4K+$0 est. gain
$6K+$0 est. gain
$12K+$0 est. gain
$24K+$0 est. gain
$250/mo
$9K+$0 est. gain
$15K+$0 est. gain
$30K+$0 est. gain
$60K+$0 est. gain
$500/mo
$18K+$0 est. gain
$30K+$0 est. gain
$60K+$0 est. gain
$120K+$0 est. gain
$1,000/mo
$36K+$0 est. gain
$60K+$0 est. gain
$120K+$0 est. gain
$240K+$0 est. gain
* Projection assumes historical CAGR of -6.4% continues. Actual returns will vary.
Your DCA Results by Date
77 purchases
Date
Price
Invested
Portfolio Value
% Gain
Gain ($)
Jan 2, 2020
$15.63
$10,000
$10,000
+0.00%
$0
Feb 3, 2020
$12.72
$10,500
$8,638
-17.73%
$-1,862
Mar 2, 2020
$11.12
$11,000
$8,052
-26.80%
$-2,948
Apr 2, 2020
$11.51
$11,500
$8,834
-23.18%
$-2,666
May 4, 2020
$12.08
$12,000
$9,771
-18.57%
$-2,229
Jun 2, 2020
$11.52
$12,500
$9,819
-21.45%
$-2,681
Jul 2, 2020
$10.98
$13,000
$9,858
-24.17%
$-3,142
Aug 3, 2020
$12.76
$13,500
$11,956
-11.43%
$-1,544
Sep 2, 2020
$12.62
$14,000
$12,325
-11.96%
$-1,675
Oct 2, 2020
$10.12
$14,500
$10,384
-28.39%
$-4,116
Nov 2, 2020
$11.03
$15,000
$11,817
-21.22%
$-3,183
Dec 2, 2020
$11.08
$15,500
$12,371
-20.19%
$-3,129
Jan 4, 2021
$12.30
$16,000
$14,233
-11.04%
$-1,767
Feb 2, 2021
$14.35
$16,500
$17,105
+3.67%
$605
Mar 2, 2021
$21.71
$17,000
$26,378
+55.17%
$9,378
Apr 5, 2021
$24.90
$17,500
$30,754
+75.74%
$13,254
May 3, 2021
$27.04
$18,000
$33,897
+88.32%
$15,897
Jun 2, 2021
$28.12
$18,500
$35,751
+93.25%
$17,251
Jul 2, 2021
$55.47
$19,000
$71,024
+273.81%
$52,024
Aug 2, 2021
$52.74
$19,500
$68,028
+248.86%
$48,528
Sep 2, 2021
$71.93
$20,000
$93,281
+366.40%
$73,281
Oct 4, 2021
$71.70
$20,500
$93,483
+356.01%
$72,983
Nov 2, 2021
$58.78
$21,000
$77,138
+267.32%
$56,138
Dec 2, 2021
$49.67
$21,500
$65,682
+205.50%
$44,182
Jan 3, 2022
$49.22
$22,000
$65,587
+198.12%
$43,587
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Frequently Asked Questions
Common questions about DCA investing in PRTA
Investing $500 per month in Prothena Corporation plc (PRTA) over the past 6 years would be worth approximately $32K today. That's -34.3% total return on $48K invested, with a -6.4% compound annual growth rate (CAGR).