U.S. utility companies' market capitalization grew 4.8% to $711.35 billion at the end of the second quarter of 2019, from $686.25 billion in the first quarter of 2019, according to data compiled by S&P Global Market Intelligence.

Of the total, 15 utilities retained their spots on the list, with only four utilities recording quarter-over-quarter percentage declines in market value of their shares.

NextEra Energy Inc., Duke Energy Corp. and Dominion Energy Inc. continued to occupy their first-, second- and third-place spots on the list, respectively. NextEra saw a 6% quarter-over-quarter increase in market cap to $98.11 billion, Duke's market cap dropped 1.9% to $64.24 billion, and Dominion posted a 1.2% increase in market cap to $62.04 billion.

Entergy Corp., which permanently shut down its 683-MW Pilgrim nuclear facility in Plymouth, Mass., on May 31 after 47 years of operations, recorded the steepest gain in market cap of 12.1% to $20.42 billion, while Exelon Corp. saw the biggest drop of 4.3% to $46.55 billion as of June 28. The two utilities, however, retained their 17th and fifth spots on the list.

California-based utilities Sempra Energy and Edison International saw the market value of their shares increase by 9.3% and 8.9%, respectively. Sempra, which ranked first among Canadian and U.S. power companies in beating expectations of Wall Street analysts during the first quarter of 2019, ended the second quarter with a market cap of $37.71 billion. Edison International's market cap grew to $21.96 billion. The utilities are expected to benefit from California Gov. Gavin Newsom's proposed $24 billion wildfire cost recovery plan to provide stability to the state's big three investor-owned utilities.

Eversource Energy improved its ranking by two spots to the 12th position after posting an 8.8% increase in market cap to $24.50 billion as of June 28. On the other hand, PPL Corp. slipped to the 15th spot from the 12th position after posting a 2.2% drop in market cap to $22.38 billion.

The S&P 500 Electric Utilities Sub Industry index posted a total return of 4.1% for the second quarter, followed by the S&P 500 Utilities index with a 3.5% gain and the S&P 500 Multi-Utilities index with a 3.2% gain. The S&P 500 index saw a total return of 4.3%.