The great advantage of hostile takeover battles for public companies is that you get a clean punch-up. The records of both parties – bidder and target – are put in the spotlight. Every claim is tested in open argument over many weeks. At the end of the process, shareholders make an informed choice. Voting turnout is usually high because only the most dozy investors fail to notice what’s at stake.

Unfortunately, the current scrap for control of seven UK investment trusts is not like that. That is most obviously the case because Saba, the US hedge fund led by Boaz Weinstein, is not making a takeover bid. Its proposal instead is to sack the boards of all seven trusts, install its own people, and, possibly, appoint itself as fund manager. So not a takeover – but very definitely an attempt by a minority shareholder (Saba has stakes in the seven trusts of between 19% and 29%) to seize control.

But another reason is that, to date, Saba has been able to lob insults at its targets while escaping detailed scrutiny of its own record. Give thanks, then, for the first piece of independent City research that nails a big deceit at the heart of Saba’s proposal. The “inconvenient truth”, as Investec puts it, is that Saba’s performance as a manager of US trusts is shockingly poor. The US raider is in no position to bang on about the “Miserable Seven” in the UK.

Saba’s main fund is its “Closed End Fund ETF” with net assets of $246m (£202.1m). Since launch in 2017, its total return is 124%, which may sound good in the abstract but is miles behind its benchmark’s return of 191%. The Saba fund has underperformed the S&P 500 index in seven out of eight years, calculates Investec.

Saba simply ignores such awkward statistics on its campaign website. Weinstein’s description of “Saba’s strong track record” is an irrelevant warble about his own skill at blackjack and chess coupled with a loose claim that the firm pursues “changes that return discounted trusts to their full NAV [net asset value]”. But the latter boast looks hollow when Investec points out two other Saba funds in the US currently trade on yawning discounts to asset value of 8.3% and 10.5%, wider than those at any of the UK trusts to which it is laying siege.

Weinstein has the opportunity to explain Saba’s failures (and its high fees) when his firm finally takes questions via a webinar on Tuesday. Here’s one: why on earth is the Keystone Positive Change trust in your sights for a “shareholder-friendly action” when its board has already proposed something that fits the bill? Keystone’s winding-up plan would allow investors to redeem in full at a 1% discount to NAV. On any measure, that is a better offer than Saba’s vague promise of “substantial” liquidity at “near” NAV.

Investec agrees with the widely held view that Saba is trying to win by “relying on investor inertia, rather than the strength of its own arguments”. Therein lies another difference from other takeover dust-ups. A simultaneous US assault on seven UK trading companies, worth £3.9bn in aggregate, would provoke maximum scrutiny. But investment trusts don’t generate the same buzz, so there is a danger that an activist US hedge fund undeservedly succeeds by slipping beneath the radar.

That would be an appalling outcome because investment trusts remain excellent collective vehicles for savers. Yes, everybody knows the frustrations – trusts can be slow to buy back shares when discounts to asset value get too wide or too entrenched. More self-reflection by boards, as Investec says, is in order. But the only short-term reflection required here should be obvious: investors in the seven trusts should vote against Saba’s grim proposals.

The other six are Baillie Gifford US Growth; Edinburgh Worldwide; Henderson Opportunities; European Smaller Companies; CQS Natural Resources Growth & Income; and Herald. Performance-wise, they’re a mixed bag. Investors in all, though, deserve an independent board rather than stealth control by a minority owner. “Time to man the barricades against an egregious and opportunistic attack,” advises Investec. Correct.