The Graduated Experience Rating Tables became effective 1/1/96 and allows for gradual maximums (caps) on debit modifications. The cap formula had been as follows until 1/1/16:
CAP = 1 + 0.00005(E + 2E/G)
Effective 1/1/16 the formula was changed to:
CAP = 1.10 + 0.0004(E/G)
Where E = expected losses and
G = State Per Claim Accident limitation divided by 25,000 rounded to the nearest 0.05.
For the following years G is equal to:
Effective Date 
Accident Limit 
Limit/ 25,000 
G Value (Rounded) 
1/1/2000 
52,000 
2.08 
2.10 
1/1/2001 
53,500 
2.14 
2.15 
1/1/2002 
57,000 
2.28 
2.30 
1/1/2003 
64,000 
2.56 
2.55 
1/1/2004 
71,500 
2.86 
2.85 
1/1/2005 
80,500 
3.22 
3.20 
1/1/2006 
92,000 
3.68 
3.70 
1/1/2007 
102,000 
4.08 
4.10 
1/1/2008 
109,500 
4.38 
4.40 
1/1/2009 
118,000 
4.72 
4.70 
1/1/2010 
125,000 
5.00 
5.00 
1/1/2011 
135,500 
5.42 
5.40 
1/1/2012 
147,000 
5.88 
5.90 
1/1/2013 
160,500 
6.42 
6.40 
1/1/2014 
172,000 
6.88 
6.90 
1/1/2015 
179,000 
7.16 
7.15 
1/1/2016 
184,500 


1/1/2017 
190,000 
7.60 
7.60 
For interstate rated risk, use the state per claim accident limit for the state with the most expected losses. Because an interstate risk is usually large, the cap formula may not have an effect.
This max or cap formula is shown as a footnote as "Cap on Modifications" in the Experience Rating Plan Manual, Part Five, Rates, at the end of the rate pages below the Table of Ballast Values chart.
To calculate a maximum mod, simply determine the expected losses for a risk and input that number into the attached spreadsheet. It will do the math.