BOSTON (Reuters) - With a volatile chief executive and a potential breakthrough product starting production, Tesla Inc TSLA.O is a challenging stock to hold.

FILE PHOTO: A Tesla sales and service center is shown in Costa Mesa, California, U.S. June 28, 2018. REUTERS/Mike Blake/File Photo

Just ask the managers of two well-known T. Rowe Price Inc TROW.O funds who came to opposite conclusions about the carmaker during the second quarter, recent commentaries show, even before Chief Executive Officer Elon Musk started tweeting about taking the carmaker private.

The split opinion matters because the enthusiasm of top investors will determine how much money Musk would need to raise.

T. Rowe Price of Baltimore remained Tesla’s third-largest investor with about 12 million shares at June 30, down 24 percent from the prior quarter.

A spokesman for the firm declined to comment.

Among other top holders, Baillie Gifford & Co and BlackRock Inc BLK.N raised their stakes during the quarter by 3 and 7 percent respectively, filings show, while Fidelity funds as a group cut Tesla by 21 percent to 11.2 million shares.

Fidelity and BlackRock spokespeople declined to comment. A Baillie Gifford representative did not immediately comment.

Managers of the T. Rowe Price Global Technology Fund PRGTX.O wrote in a June 30 semiannual report that in regards to Tesla, "We trimmed our position significantly as the stock rose, feeling that the risk/return trade-off had grown less attractive at higher valuation levels."

The fund, led by Joshua Spencer, held 505,283 Tesla shares at the end of June, disclosures show, less than a sixth of the 3,192,850 shares held at the end of March, the biggest recent sale among funds tracked by Thomson Reuters Eikon. At Dec. 31 it had 2,250,300 Tesla shares.

Tesla has risen and fallen in Spencer’s holdings before, which he has termed an “on-again, off-again relationship.”

Tesla shares finished June at $342.95, up 29 percent from the end of the March. They closed Tuesday at $321.90, up 4 percent.

While Spencer's fund was selling Tesla, its second-largest buyer in the second quarter was T. Rowe Price Blue Chip Growth Fund TRBCX.O. It had 1,298,653 Tesla shares at June 30, up from 821,953 at March 31, disclosures show.

In a quarterly review as of June 30, managers led by Larry Puglia wrote they added shares “as we were encouraged by the company’s announcement of incremental progress toward its Model 3 production target.”

“The company also reaffirmed its guidance of achieving positive earnings and cash flow in the second half of 2018 and reiterated that an additional capital raise would not be necessary to fuel operations through the end of the year,” they wrote.