New York City Mayor Bill de Blasio asked the city’s pension funds to unload their gunmaker stocks on Friday — but that would deny them one of the safest ways to make money in unsafe times.

Consider the performance of Smith & Wesson Holding Corp., the 163-year-old firearms manufacturer whose shares are up 100 percent this year and 359 percent over the past five years — that’s more than twice the gain of Apple since late 2010.

S&W shares have come into focus in recent months in the wake of the spate of mass murders across the country.

The focus has brought some hostile fire — like from Mayor de Blasio — as well as a spike in sales.

For example, on Nov. 27, Black Friday, many gun shops reported record sales and the FBI ran more than 185,000 background checks — up 5 percent from last year.

In fact, within three days of the last 10 mass murders in the country, S&W shares have risen nine times.

The shares gained 3.4 percent on Friday to close at $18.99.

In the latest example of the phenomena, S&W shares gained 3.6 percent since Dec. 2, the day of the San Bernardino, Calif., terrorist attack that killed 14 people and injured 21.

A Smith & Wesson M&P .223-caliber assault rifle was used in the attack.

And for its most recent quarter, the gunmaker reported a 12.1 percent increase in sales, as its customer mix rapidly changes from hunting-license holders to concealed-carry permit holders.

The shares of a second gunmaker, Sturm, Ruger & Company, have gained 57 percent this year — and are up 242 percent over the last five years. The company closed Friday at $54.33, up 2.6 percent.

Its revenue was up 22 percent in the three months ended Sept. 26.

Shares of the Southport, Conn., company are up 3.3 percent since Dec. 2.