---
kind: "section"
citation: "45 C.F.R. § 158.220"
title: "45"
number: "158.220"
heading: "Aggregation of data in calculating an issuer's medical loss ratio."
url: "https://uscodex.org/cfr/45/158.220"
---

# §158.220. Aggregation of data in calculating an issuer's medical loss ratio.

- (a) **Aggregation by State and by market.** In general, an issuer's MLR must be calculated separately for the large group market, small group market and individual market within each State. However, if a State requires the small group market and individual market to be merged, then the data reported separately under subpart A of this part for the small group and individual market in that State must be merged for purposes of calculating an issuer's MLR and any rebates owing.
- (b) **Years of data to include in calculating MLR.** Subject to paragraphs [(c)](#c) and [(d)](#d) of this section, an issuer's MLR for an MLR reporting year is calculated according to the formula in [§ 158.221](/cfr/45/158.221.md) of this subpart and aggregating the data reported under this part for the following 3-year period:
  - (1) The data for the MLR reporting year whose MLR is being calculated; and
  - (2) **The data for the two prior MLR reporting years.**
- (c) **Requirements for MLR reporting years 2011 and 2012.**
  - (1) For the 2011 MLR reporting year, an issuer's MLR is calculated using the data reported under this part for the 2011 MLR reporting year only.
  - (2) **For the 2012 MLR reporting year—**
    - (i) If an issuer's experience for the 2012 MLR reporting year is fully credible, as defined in [§ 158.230](/cfr/45/158.230.md) of this subpart, an issuer's MLR is calculated using the data reported under this part for the 2012 MLR reporting year.
    - (ii) If an issuer's experience for the 2012 MLR reporting year is partially credible or non-credible, as defined in [§ 158.230](/cfr/45/158.230.md) of this subpart, an issuer's MLR is calculated using the data reported under this part for the 2011 MLR reporting year and the 2012 MLR reporting year.
- (d) **Requirements for MLR reporting years 2013 and 2014 for the student market only.**
  - (1) For the 2013 MLR reporting year, an issuer's MLR is calculated using the data reported under this part for the 2013 MLR reporting year only.
  - (2) **For the 2014 MLR reporting year—**
    - (i) If an issuer's experience for the 2014 MLR reporting year is fully credible, as defined in [§ 158.230](/cfr/45/158.230.md) of this subpart, an issuer's MLR is calculated using the data reported under this part for the 2014 MLR reporting year.
    - (ii) If an issuer's experience for the 2014 MLR reporting year is partially credible or non-credible, as defined in [§ 158.230](/cfr/45/158.230.md) of this subpart, an issuer's MLR is calculated using the data reported under this part for the 2013 MLR reporting year and the 2014 MLR reporting year.

## Notes

### Amendments

[75 FR 74921, Dec. 1, 2010, as amended at 77 FR 16469, Mar. 21, 2012; 79 FR 30352, May 27, 2014]

### Authority

Authority: 42 U.S.C. 300gg-18.

### Source

Source: 75 FR 74921, Dec. 1, 2010, unless otherwise noted.

### Amendments

[75 FR 74921, Dec. 1, 2010, as amended at 77 FR 16469, Mar. 21, 2012; 79 FR 30352, May 27, 2014]