The aim of this article is to investigate the influence of market interest rate on Participation 30 index companies. The interest rate of Turkish government bonds traded in the secondary market was used for representing market interest rate. The study uses a panel data of 41 Participation index companies from 2011 to 2017. Using LM bootstrap panel cointegration test, we obtained results showing that the market interest rate affects the stock prices of P30 index companies. This effect is negative for ALBRK, KONYA, BAGFS, KOZAL and PRKME, but positive for all other companies. The least affected company from market interest rate is TTKOM, while the most affected company is LOGO. Moreover, it is noteworthy that 5 of the 10 companies with the lowest long-run coefficient are operating in the construction-raw material industry.