BOSTON (Reuters) - For months, activist investor William Ackman promised to rebuild his record. Now he has some numbers to prove it.

FILE PHOTO: William 'Bill' Ackman, CEO and Portfolio Manager of Pershing Square Capital Management, speaks during the Sohn Investment Conference in New York City, U.S., May 8, 2017. REUTERS/Brendan McDermid

Since Jan. 1, Pershing Square Holdings has gained 31.9 percent, making it the best start to a year in the firm’s 15-year history, Ackman wrote in a letter released on Monday.

More importantly, Ackman laid out how his hedge fund is essentially transforming itself into a holding company that owns stakes in public companies and offers a helping hand to struggling management teams to resurrect once-strong returns.

“We attribute our improved performance to initiatives that we have implemented over the last 18 months,” he wrote.

With his own transformation on firmer ground, Ackman said he can again help others. “Pershing Square, as a large influential investor with a track record for successful turnarounds, can provide management with the required runway and necessary long-term backing to succeed.”

For years Ackman earned billions for himself and clients while growing Pershing Square Capital Management into a roughly $20 billion firm. But in 2015 a soured bet on drug company Valeant paved the way for three years of losses, when investors ran for the exits, shrinking assets to $8 billion.

Now Ackman’s publicly traded fund, Pershing Square Holdings, makes up roughly three-quarters of the firm’s $8 billion in assets and the capital is stable because investors have to sell to another investor before exiting.

Permanent capital will help improve his own returns over time and let him become a helpmate to struggling companies, Ackman wrote.

To get here, Ackman went back to his roots and last year laid off staff, told his investor relations executives to stop raising new capital and re-dedicated himself to researching investment ideas instead of jetting around the world to visit with clients.

Ackman and his colleagues now own more than 20 percent of Pershing Square Holdings’ outstanding shares, he wrote.

His business, he explained to anyone who does not know about investments in companies like Chipotle and Canadian Pacific , is buying companies at a discount and helping them flourish again.

Over the last months, Ackman, once a fixture at conferences and on television, adopted a more low-key style, which he is translating to portfolio companies as well.

He said he has a lot of influence but prefers to use it “sparingly.” “Occasionally, we will ask a question, share an idea, or raise an issue. Most of the time, our CEOs rarely hear from us,” Ackman wrote, saying they call him. “We view our job as oversight, not day-to-day management.”