When Zero Investment Does Not Mean Zero Financial Interest: Risks of Interpreting Ownership Data in Open Payments.

Background Open Payments is a national transparency program administered by the Centers for Medicare and Medicaid Services (CMS) that publicly reports financial relationships between reporting entities and covered recipients, including ownership and investment interests. The ownership file reports the amount invested during a single program year alongside the cumulative value of the interest held, so a report of zero investment accompanied by a positive cumulative value cannot establish when or how the interest was acquired. We measured how often this combination appears and how much investment history is recovered by reviewing earlier program years. Materials and methods We conducted a retrospective analysis of the CMS Open Payments ownership and investment interest detail files for program years 2014 through 2024, comprising 46,015 records and 43,097 physician-entity-years among 10,181 physicians. Records were aggregated to the physician-entity-year by summing annual investment and taking the maximum reported cumulative value. A physician-entity-year qualified when summed annual investment was zero, and maximum cumulative value was greater than zero. For each qualifying observation, we determined whether a positive investment had been reported for the same physician-entity relationship in an earlier program year, and we repeated the analysis at review depths of one to five prior years. Sensitivity analyses addressed linkage assumptions and a restricted definition requiring cumulative value above $1,000. Results Published records reporting zero annual investment with positive cumulative value increased from 312 of 5,459 (5.7%) in 2014 to 3,551 of 4,834 (73.5%) in 2024. The largest single-year change occurred between program years 2018 and 2019, coinciding with the boundary between archived and current publication versions; this discontinuity is unexplained, and the series should not be read as a continuous temporal trend. Among 19,798 qualifying physician-entity-years, earlier records reported a positive investment for the same relationship in 10,300 (52.0%), while 6,368 (32.2%) had no positive investment reported anywhere within the study window. Of the 10,300 prior investments identified through review of the complete available history, reviewing one prior year captured 3,446 (33.5%), three prior years captured 7,436 (72.2%), and five prior years captured 9,121 (88.6%). Across the principal linkage sensitivity analyses, the estimates ranged from 8,386 of 16,406 (51.1%) to 7,939 of 14,945 (53.1%). Conclusions Zero annual investment does not establish that an ownership interest was acquired without capital, and a prior reported investment does not establish the origin of a later reported interest. The public files contain no persistent identifier for an individual ownership interest, so an earlier investment and a later cumulative value within the same physician-entity relationship may describe different instruments. A single program year is a weak basis for characterizing a physician's ownership interest. Longitudinal review of at least three to five prior program years is warranted before a reported ownership interest is acted upon. Only the effect of review depth was evaluated empirically; verification of physician and entity identity and corroboration with source documents proportionate to the consequences of the decision are proposed practices that have not been validated.